2020-10-21T11:16:51Zhttp://edoc.mpg.de/ac_p_oai.ploai:edoc.mpg.de:201832014-10-1343:960
The asymptotic region of the potential energy surfaces relevant for the O(3P)+O2(X3Σg-) ⇋ O3 reaction
Rosmus, P.
Palmieri, P.
Schinke, R.
notspecified
The potential energy functions for all states of ozone correlating with the lowest O(P-3)+O-2(X (3)Sigma(g)(-)) asymptote have been calculated in the asymptotic region employing correlated electronic wave functions. For linear ozone, the (s)Sigma states (s=1,3, and 5) lie above the corresponding (s)Pi states. For bent geometries the Pi states split into Renner-Teller components with A(') and A(') symmetry, respectively. While the (1)Pi and (3)Pi states lead to bent-bent Renner-Teller pairs, the (5)Pi state gives rise to a linear/linear pair of states. The different spin multiplets emerging from the Pi states cross for valence angles around 160degrees and the (1)A(') component becomes the lowest one. The matrix elements of the spin-orbit operator have also been calculated. They are dominated by the atomic P-3 contributions and their dependence on the mutual orientation of the O-2 molecule and the O atom is small. In the regions where the states correlating to the linear (1,3,5)Pi cross, i.e., for valence angles between 150degrees and 180degrees and close to 90degrees, the mixing among the singlet, triplet, and quintet states is strong and the electron spin quantum number is no longer a good quantum number. (C) 2002 American Institute of Physics.
2002
Article
http://edoc.mpg.de/20183
urn:ISSN:0021-9606
Journal of Chemical Physics, v.117, 4871-4877 (2002)
en
oai:edoc.mpg.de:201852014-10-1343:960
Resonances in SN2 reactions: Two-mode quantum calculations for Cl⁻+CH3Br on a coupled-cluster potential energy surface
Schmatz, S.
Botschwina, P.
Hauschildt, J.
Schinke, R.
notspecified
An effective two-dimensional potential energy surface has been constructed for the SN2 reaction Cl-+CH3Br-->ClCH3+Br- from coupled-cluster calculations with a large basis set. In the quantum dynamics calculations Radau coordinates were employed to describe the Cl-C and C-Br stretching modes. Making use of the filter diagonalization method and an optical potential, bound states as well as resonance states up to energies far above the dissociation threshold have been calculated. The resonance widths fluctuate over several orders of magnitude. In addition to a majority of Feshbach-type resonances there are also exceedingly long-lived shape resonances, which can only decay by tunneling. Owing to a smaller width of the potential barrier and a larger density of states, tunneling through the barrier is more important for Cl-+CH3Br than for Cl-+CH3Cl despite the larger total mass of this system. Excitation of the C-Br stretching vibration enhances the tunneling probability of the entrance channel complex. (C) 2002 American Institute of Physics.
2002
Article
http://edoc.mpg.de/20185
urn:ISSN:0021-9606
Journal of Chemical Physics, v.117, 9710-9718 (2002)
en
oai:edoc.mpg.de:201862014-10-1343:960
Relationship between mode specific and thermal unimolecular rate constants for HOCl -> OH+Cl dissociation
Song, K. H.
Sun, L. P.
Hase, W. L.
Grebenshchikov, S. Y.
Schinke, R.
notspecified
Recent quantum dynamical calculations [Hauschildt, J.; et al. Chem. Phys.. Lett. 1999, 300, 569] have shown that HOCl --> OH + Cl dissociation on the ground-state potential energy surface, and for J = 0, occurs predominantly via isolated compound-state resonances, whose rates are highly mode-specific. In this work, these resonance rates are averaged to calculate the HOCl --> OH + Cl unimolecular rate constant as a function of temperature and pressure. The result is compared with the standard pressure and temperature dependent RRKM unimolecular rate constant. It is found that the state-specificity makes the pressure- dependent rates significantly lower than the RRKM rates in the intermediate pressure regime.
2002
Article
http://edoc.mpg.de/20186
urn:ISSN:1089-5639
Journal of Physical Chemistry A, v.106, 8339-8344 (2002)
en
oai:edoc.mpg.de:201912014-10-1343:960
Highly excited motion in molecules: Saddle-node bifurcations and their fingerprints in vibrational spectra
Joyeux, M.
Farantos, S. C.
Schinke, R.
notspecified
The vibrational motion of highly excited molecules is discussed in terms of exact quantum and classical mechanics calculations, employing global potential energy surfaces, as well as in terms of a spectroscopic Hamiltonian and its semiclassical limit. The main focus is saddle-node bifurcations and their influence on the spectrum. The general features are illustrated by three examples, which despite their quite different intramolecular motions have several aspects in common: HCP, HOCl, and HOBr. In all three cases a 1:2 Fermi resonance is the ultimate cause of the complications observed in the spectra.
2002
Article
http://edoc.mpg.de/20191
urn:ISSN:1089-5639
Journal of Physical Chemistry A, v.106, 5407-5421 (2002)
en
oai:edoc.mpg.de:208762014-10-1343:960
The vibrational energies of ozone up to the dissociation threshold: Dynamics calculations on an accurate potential energy surface
Siebert, R.
Fleurat-Lessard, P.
Schinke, R.
Bittererova, M.
Farantos, S. C.
notspecified
We present an ab initio potential energy surface for the ground electronic state of ozone. It is global, i.e., it covers the three identical C2v (open) minima, the D3h (ring) minimum, as well as the O(3P)+O2(3Σg-) dissociation threshold. The electronic structure calculations are performed at the multireference configuration interaction level with complete active space self-consistent-field reference functions and correlation consistent polarized quadruple zeta atomic basis functions. Two of the O-O bond distances, R1 and R2, and the O-O-O bending angle are varied on a regular grid (ca. 5000 points with R1 ≥ R2). An analytical representation is obtained by a three-dimensional cubic spline. The calculated potential energy surface has a tiny dissociation barrier and a shallow van der Waals minimum in the exit channel. The ring minimum is separated from the three open minima by a high potential barrier and therefore presumably does not influence the low-temperature kinetics. The dissociation energy is reproduced up to 90% of the experimental value. All bound states of nonrotating ozone up to more than 99% of the dissociation energy are calculated using the filter diagonalization technique and employing Jacobi coordinates. The three lowest transition energies for 16O3 are 1101.9 cm-1 (1103.14 cm-1), 698.5 cm-1 (700.93 cm-1), and 1043.9 cm-1 (1042.14 cm-1) for the symmetric stretch, the bending, and the antisymmetric stretch modes, respectively; the numbers in parentheses are the experimental values. The root-mean-square error for all measured transition energies for 16O3 is only 5 cm-1. The comparison is equally favorable for all other isotopomers, for which experimental frequencies are available. The assignment is made in terms of normal modes, despite the observation that with increasing energy an increasing number of states acquires local-mode character. At energies close to the threshold a large fraction of states is still unambiguously assignable, particularly those of the overtone progressions. This is in accord with the existence of stable classical periodic orbits up to very high energies. (C) 2002 American Institute of Physics.
2002
Article
http://edoc.mpg.de/20876
urn:ISSN:0021-9606
Journal of Chemical Physics, v.116, 9749-9767 (2002)
en
oai:edoc.mpg.de:1758762014-10-1443:960
van der Waals states in ozone and their influence on the threshold spectrum of O3(X1A1). I. Bound states.
Grebenshchikov, S. Y.
Schinke, R.
Fleurat-Lessard, P.
Joyeux, M.
notspecified
2003
Article
http://edoc.mpg.de/175876
urn:ISSN:0021-9606
Journal of Chemical Physics, v.119, 6512-6523 (2003)
en
oai:edoc.mpg.de:1758782014-10-1443:960
Comment on 'Rate coefficients for photoinitiated NO2 unimolecular decomposition: energy dependence in the threshold regime' [Chem. Phys. Lett. 358 (2002) 71]
Abel, B.
Grebenshchikov, S. Y.
Schinke, R.
Schwarzer, D.
notspecified
2003
Article
http://edoc.mpg.de/175878
urn:ISSN:0009-2614
Chemical Physics Letters, v.368, 252-256 (2003)
en
oai:edoc.mpg.de:1759572014-10-1443:960
Formation of ozone: Metastable states and anomalous isotope effect
Babikov, D.
Kendrick, B. K.
Walker, R. B.
Pack, R. T.
Fleurat-Lesard, P.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/175957
urn:ISSN:0021-9606
Journal of Chemical Physics, v.119, 2577-2589 (2003)
en
oai:edoc.mpg.de:1759582014-10-1443:960
Isotope dependence of the O+O2 exchange reaction: Experiment and theory
Fleurat-Lessard, P.
Grebenshchikov, S. Y.
Schinke, R.
Janssen, C.
Krankowsky, D.
notspecified
2003
Article
http://edoc.mpg.de/175958
urn:ISSN:0021-9606
Journal of Chemical Physics, v.119, 4700-4712 (2003)
en
oai:edoc.mpg.de:1759592014-10-1443:960
Isotope dependence of the lifetime of ozone complexes formed in O+O2 collisions
Schinke, R.
Fleurat-Lessard, P.
Grebenshchikov, S. Y.
notspecified
2003
Article
http://edoc.mpg.de/175959
urn:ISSN:1463-9076
Physical Chemistry Chemical Physics, v.5, 1966-1969 (2003)
en
oai:edoc.mpg.de:1759612014-10-1443:960
Metastable states of ozone calculated on an accurate potential energy surface
Babikov, D.
Kendrick, B. K.
Walker, R. B.
Pack, R. T.
Fleurat-Lesard, P.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/175961
urn:ISSN:0021-9606
Journal of Chemical Physics, v.118, 6298-6308 (2003)
en
oai:edoc.mpg.de:1759622014-10-1443:960
NO2: Global potential energy surfaces of the ground (12A1) and the first excited (12B2) electronic states
Kurkal, V.
Fleurat-Lessard, P.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/175962
urn:ISSN:0021-9606
Journal of Chemical Physics, v.119, 1489-1501 (2003)
en
oai:edoc.mpg.de:1759912014-10-1443:960
The bound state spectrum of HOBr up to the dissociation limit: Evolution of saddle-node bifurcations
Azzam, T.
Schinke, R.
Farantos, S. C.
Joyeux, M.
Peterson, K. A.
notspecified
2003
Article
http://edoc.mpg.de/175991
urn:ISSN:0021-9606
Journal of Chemical Physics, v.118, 9643-9652 (2003)
en
oai:edoc.mpg.de:1759922014-10-1443:960
The effect of spin-orbit coupling in complex forming O(3P) + O2 collisions
Tashiro, M.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/175992
urn:ISSN:0021-9606
Journal of Chemical Physics, v.119, 10186-10193 (2003)
en
oai:edoc.mpg.de:1759962014-10-1443:960
The ultra-violet photodissociation of ozone revisited
Qu, Z. W.
Zhu, H.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/175996
urn:ISSN:0009-2614
Chemical Physics Letters, v.377, 359-366 (2003)
en
oai:edoc.mpg.de:1759972014-10-1443:960
The vibrational spectrum of cyclic ozone
Siebert, R.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/175997
urn:ISSN:0021-9606
Journal of Chemical Physics, v.119, 3092-3097 (2003)
en
oai:edoc.mpg.de:1759982014-10-1443:960
Theoretical investigation of the temperature dependence of the O+O2 exchange reaction
Fleurat-Lessard, P.
Grebenshchikov, S. Y.
Siebert, R.
Schinke, R.
Halberstadt, N.
notspecified
2003
Article
http://edoc.mpg.de/175998
urn:ISSN:0021-9606
Journal of Chemical Physics, v.118, 610-621 (2003)
en
oai:edoc.mpg.de:1759992014-10-1443:960
Theory of molecular bound states including Σ-Π vibronic interaction
Poluyanov, L.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/175999
urn:ISSN:0301-0104
Chemical Physics, v.288, 123-136 (2003)
en
oai:edoc.mpg.de:1760002014-10-1443:960
Time-dependent wave packet study of the O+O2 (υ=0,j=0) exchange reaction
Yeh, K. L.
Xie, D. Q.
Zhang, D. H.
Lee, S. Y.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/176000
urn:ISSN:1089-5639
Journal of Physical Chemistry A, v.107, 7215-7219 (2003)
en
oai:edoc.mpg.de:1760012014-10-1443:960
Two-dimensional neutral donors in electric fields
Ivanov, M. V.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/176001
urn:ISSN:0953-8984
Journal of Physics-Condensed Matter, v.15, 5909-5913 (2003)
en
oai:edoc.mpg.de:1904552007-03-2843:960
Quantum origin of an anomalous isotope effect in ozone formation
Babikov, D.
Kendrick, B. K.
Walker, R. B.
Pack, R. T.
Schinke, R.
notspecified
2003
Article
http://edoc.mpg.de/190455
Chemical Physics Letters, v.372, 686-691 (2003)
en
oai:edoc.mpg.de:1904562007-03-2843:960
State-specific dynamics of unimolecular dissociation
Grebenshchikov, S.
Schinke, R.
Hase, W. L.
notspecified
Elsevier
2003
InBook
http://edoc.mpg.de/190456
Comprehensive Chemical Kinetics, Part 1, 105-242 (2003)
en
oai:edoc.mpg.de:2196372007-03-2843:960
Intra- and intermolecular energy transfer in highly excited ozone complexes
Ivanov, M. V.
Grebenshchikov, S. Y.
Schinke, R.
notspecified
2004
Article
http://edoc.mpg.de/219637
urn:ISSN:0021-9606
Journal of Chemical Physics, v.120, 10015-10024 (2004)
en
oai:edoc.mpg.de:2196382007-03-2843:960
Two-dimensional analogs of the H2+ ion in stationary electric fields
Ivanov, M. V.
Schinke, R.
notspecified
2004
Article
http://edoc.mpg.de/219638
urn:ISSN:1098-0121
Physical Review B, v.69 (2004)
en
oai:edoc.mpg.de:2196402007-03-2843:960
Resonance spectrum and dissociation dynamics of ozone in the 3B2 electronically excited state: Experiment and theory
Deppe, S. F.
Wachsmuth, U.
Abel, B.
Bittererova, M.
Grebenshchikov, S. Y.
Siebert, R.
Schinke, R.
notspecified
2004
Article
http://edoc.mpg.de/219640
urn:ISSN:0021-9606
Journal of Chemical Physics, v.121, 5191-5200 (2004)
en
oai:edoc.mpg.de:2196442007-03-2843:960
On spin-forbidden processes in the ultra-violet photodissociation of ozone
Zhu, H.
Qu, Z. W.
Tashiro, M.
Schinke, R.
notspecified
2004
Article
http://edoc.mpg.de/219644
urn:ISSN:0009-2614
Chemical Physics Letters, v.384, 45-51 (2004)
en
oai:edoc.mpg.de:2196462007-03-2843:960
Semiclassical dynamics of the van der Waals states in O3(X 1A1)
Joyeux, M.
Schinke, R.
Grebenshchikov, S. Y.
notspecified
2004
Article
http://edoc.mpg.de/219646
urn:ISSN:0021-9606
Journal of Chemical Physics, v.120, 7426-7437 (2004)
en
oai:edoc.mpg.de:2196472007-03-2843:960
The Huggins band of ozone: A theoretical analysis
Qu, Z. W.
Zhu, H.
Grebenshchikov, S. Y.
Schinke, R.
Farantos, S. C.
notspecified
2004
Article
http://edoc.mpg.de/219647
urn:ISSN:0021-9606
Journal of Chemical Physics, v.121, 11731-11745 (2004)
en
oai:edoc.mpg.de:2196482007-03-2843:960
The Huggins band of ozone: Unambiguous electronic and vibrational assignment
Qu, Z. W.
Zhu, H.
Tashiro, M.
Schinke, R.
Farantos, S. C.
notspecified
2004
Article
http://edoc.mpg.de/219648
urn:ISSN:0021-9606
Journal of Chemical Physics, v.120, 6811-6814 (2004)
en
oai:edoc.mpg.de:2198792007-03-2843:960
On the transition-state region of the O(3P) + O2(3Σg-) potential energy surface
Schinke, Reinhard
Fleurat-Lessard, Paul
notspecified
2004
Article
http://edoc.mpg.de/219879
Journal of Chemical Physics, v.121, 5789-5793 (2004)
en
oai:edoc.mpg.de:2263092006-04-2043:960
Defect turbulence and generalized statistical mechanics
Daniels, Karen E.
Beck, Christian
Bodenschatz, Eberhard
expertsonly
2004
Article
http://edoc.mpg.de/226309
info:doi/10.1016/j.physd.2004.01.033
Physica D, v.193, 208-217 (2004)
en
oai:edoc.mpg.de:2263102006-04-2043:960
Experimental Lagrangian acceleration probability density function measurement
Mordant, Nicolas
Crawford, Alice M.
Bodenschatz, Eberhard
expertsonly
2004
Article
http://edoc.mpg.de/226310
info:doi/10.1016/j.physd.2004.01.041
Physica D, v.193, 245-251 (2004)
en
oai:edoc.mpg.de:2263112006-04-2043:960
Dislocation dynamics in Rayleigh-Bénard convection
Walter, T.
Bodenschatz, E.
Pesch, W.
expertsonly
Theoretical results on the dynamics of dislocations in Rayleigh-Benard convection are reported both for a Swift-Hohenberg model and the Oberbeck-Boussinesq equations. For intermediate Prandtl numbers the motion of dislocations is found to be driven by the superposition of two independent contributions: (i) the Peach-Koehler force and (ii) an advection force on the dislocation core by its self-generated mean flow. Their competition allows to explain the experimentally observed bound dislocation pairs.
2004
Article
http://edoc.mpg.de/226311
info:doi/10.1063/1.1772231
Chaos, v.14, 933-939 (2004)
en
oai:edoc.mpg.de:2263122006-04-2043:960
Statistics of defect trajectories in spatio-temporal chaos in inclined layer convection and the complex Ginzburg-Landau equation
Huepe, Cristián
Riecke, Hermann
Daniels, Karen
Bodenschatz, Eberhard
expertsonly
For spatio-temporal chaos observed in numerical simulations of the complex Ginzburg-Landau equation (CGL) and in experiments on inclined-layer convection (ILC) we report numerical and experimental data on the statistics of defects and of defect loops. These loops consist of defect trajectories in space-time that are connected to each other through the pairwise annihilation or creation of the associated defects. While most such loops are small and contain only a few defects, the loop distribution functions decay only slowly with the quantities associated with the loop size, consistent with power-law behavior. For the CGL, two of the three power-law exponents are found to agree, within our computational precision, with those from previous investigations of a simple lattice model. In certain parameter regimes of the CGL and ILC, our results for the single-defect statistics show significant deviations from the previously reported findings that the defect dynamics are consistent with those of random walkers that are created with fixed probability and annihilated through random collisions.
2004
Article
http://edoc.mpg.de/226312
info:doi/10.1063/1.1778495
Chaos, v.14, 864-874 (2004)
en
oai:edoc.mpg.de:2263132006-04-2043:960
A random synthetic jet array driven turbulence tank
Variano, Evan A.
Bodenschatz, Eberhard
Cowen, Edwin A.
expertsonly
2004
Article
http://edoc.mpg.de/226313
urn:ISSN:0723-4864
info:doi/10.1007/s00348-004-0833-z
Experiments in Fluids, v.37, 613-615 (2004)
en
oai:edoc.mpg.de:2263142006-04-2043:960
Three-Dimensional Structure of Lagrangian Acceleration in Turbulent Flows
Mordant, Nicolas
Crawford, Alice M.
Bodenschatz, Eberhard
expertsonly
We report experimental results on the three-dimensional Lagrangian acceleration in highly turbulent flows. Tracer particles are tracked optically using four silicon strip detectors from high energy physics that provide high temporal and spatial resolution. The components of the acceleration are shown to be statistically dependent. The probability density function of the acceleration magnitude is comparable to a log-normal distribution. Assuming isotropy, a log-normal distribution of the magnitude can account for the observed dependency of the components. The time dynamics of the acceleration components is found to be typical of the dissipation scales, whereas the magnitude evolves over longer times, possibly close to the integral time scale.
2004
Article
http://edoc.mpg.de/226314
info:doi/10.1103/PhysRevLett.93.214501
Physical Review Letters, v.93, 214501-1-214501-4 (2004)
en
oai:edoc.mpg.de:2263152006-04-2043:960
Experiments with Dictyostelium Discoidium Amoebae in Different Geometries
Voelz, Camilla
Bodenschatz, Eberhard
expertsonly
World Scientific
2004
InBook
http://edoc.mpg.de/226315
Dynamics and Bifurcation of Patterns in Dissipative Systems, 372-385 (2004)
en
oai:edoc.mpg.de:2263162006-04-2043:960
Using microfluidic channel networks to generate gradients for studying cell migration
Rhoads, D. S.
Nadkarni, S. M.
Song, L.
Voeltz, C.
Bodenschatz, E.
Guan, J.-L.
expertsonly
gradient; microfluidics; migration; chemoattractant; microenvironment; nanobiotechnology
In this chapter, we will discuss a method for the generation of gradients that can be quantitatively used for studying directional cell migration. Microfluidic networks, which serially split and remix small volumes of solutions under laminar flow conditions to generate a series of microchannels of increasing protein concentration. At a juncture of these microchannels, where a single broad channel is formed, a protein concentration gradient can be easily achieved. This method is highly useful because of the ability with which we can control, manipulate and analyze chemical gradients and cells' chemotactic behavior in a quantitative manner.
Humana Press
2004
InBook
http://edoc.mpg.de/226316
Cell Migration: Developmental Methods and Protocols, 347-358 (2004)
en
oai:edoc.mpg.de:2265762006-04-2043:960
Experimental apparatus and sample preparation techniques for directional solidification
Utter, B.
Ragnarsson, R.
Bodenschatz, E.
expertsonly
2005
Article
http://edoc.mpg.de/226576
info:doi/10.1063/1.1807592
Review of Scientific Instruments, v.76, 013906-1-013906-9 (2005)
en
oai:edoc.mpg.de:2265872006-04-2043:960
Joint Statistics of the Lagrangian Acceleration and Velocity in Fully Developed Turbulence
Crawford, Alice M.
Mordant, Nicolas
Bodenschatz, Eberhard
expertsonly
We report experimental results on the joint statistics of the Lagrangian acceleration and velocity in highly turbulent flows. The acceleration was measured up to a microscale Reynolds number R(lambda)=690 using high speed silicon strip detectors from high energy physics. The acceleration variance was observed to be strongly dependent on the velocity, following a Heisenberg-Yaglom-like u(9/2) increase. However, the shape of the probability density functions of the acceleration component conditioned on the same component of the velocity when normalized by the acceleration variance was observed to be independent of velocity and to coincide with the unconditional probability density function of the acceleration components. This observation imposes a strong mathematical constraint on the possible functional form of the acceleration probability distribution function.
2005
Article
http://edoc.mpg.de/226587
info:doi/10.1103/PhysRevLett.94.024501
Physical Review Letters, v.94, 024501-1-024501-4 (2005)
en
oai:edoc.mpg.de:2265902006-04-2043:960
Tectonic microplates in a wax model of sea-floor spreading
Katz, Richard F.
Ragnarsson, Rolf
Bodenschatz, Eberhard
expertsonly
2005
Article
http://edoc.mpg.de/226590
info:doi/10.1088/1367-2630/7/1/037
New Journal of Physics, v.7, 37 (37-01)-37 (37-11) (2005)
en
oai:edoc.mpg.de:2447842007-03-2843:960
The effect of zero-point energy differences on the isotope dependence of the formation of ozone: A classical trajectory study
Schinke, R.
Fleurat-Lessard, P.
expertsonly
2005
Article
http://edoc.mpg.de/244784
The Journal of Chemical Physics, v.122, 094317-1-094317-9 (2005)
en
oai:edoc.mpg.de:2447852007-03-2843:960
Experimental and theoretical investigation of the reaction NH(X3∑-)+H(2S) → N(4S)+H2(X1∑+g)
Adam, L.
Hack, W.
Zhu, H.
Qu, Z.-W.
Schinke, R.
notspecified
2005
Article
http://edoc.mpg.de/244785
The Journal of Chemical Physics, v.122, 114301-1-114301-7 (2005)
en
oai:edoc.mpg.de:2494912007-03-2843:960
Experimental and theoretical investigation of the reactions NH(X3Σ⁻) + D(2S) → ND(X3Σ⁻) + H(2S) and NH(X3Σ⁻) + D(2S) → N(4S) + HD(X1Σ⁺g)
Qu, Z.-W.
Zhu, H.
Schinke, R.
Adam, L.
Hack, W.
notspecified
2005
Article
http://edoc.mpg.de/249491
Journal of Chemical Physics, v.122 (2005)
en
oai:edoc.mpg.de:2494922007-03-2843:960
The triplet channel in the photodissociation of ozone in the Hartley band: Classical trajectory surface hopping analysis
Qu, Z. H.
Zhu, H.
Grebenshchikov, S. Yu.
Schinke, R.
notspecified
2005
Article
http://edoc.mpg.de/249492
Journal of Chemical Physics, v.122 (2005)
en
oai:edoc.mpg.de:2494932007-03-2843:960
Assessment of the ozone isotope effect
Mauersberger, K.
Krankowsky, D.
Janssen, C.
Schinke, R.
notspecified
2005
Article
http://edoc.mpg.de/249493
Advances in Atomic, Molecular and Optical Physics, v.50, 1-54 (2005)
en
oai:edoc.mpg.de:2494942007-03-2843:960
Temperature dependent energy transfer in Ar-O3 collisions
Ivanov, Mikhail V.
Schinke, Reinhard
notspecified
2005
Article
http://edoc.mpg.de/249494
info:doi/10.1063/1.1927526
Journal of Chemical Physics, v.122 (2005)
en
oai:edoc.mpg.de:2617562007-03-3043:960
Measurement of Lagrangian Acceleration in Turbulent Flows Using the Laser Doppler Technique Optical Methods of Flow Investigation
Nobach, H.
Kinzel, M.
Tropea, C.
popular
The use of the laser Doppler technique for measuring Lagrangian acceleration with a high spatial resolution is introduced. The requirements in system alignment and accuracy of signal processing is estimated. Specifications of the optical design and the signal processing are given.
2006
Article
http://edoc.mpg.de/261756
Proceedings SPIE, v.6262 (2006)
en
oai:edoc.mpg.de:2622522006-04-2043:960
Double Dendrite Growth in Solidification
Utter, Brian
Bodenschatz, Eberhard
expertsonly
We present experiments on the doublon growth morphology in directional solidification. Samples used are succinonitrile with small amounts of poly(ethylene oxide), acetone, or camphor as the solute. Doublons, or symmetry-broken dendrites, are generic diffusion-limited growth structures expected at large undercooling and low anisotropy. Low anisotropy growth is achieved by selecting a grain near the {111} plane leading to either seaweed (dense branching morphology) or doublon growth depending on experimental parameters. We find selection of doublons to be strongly dependent on solute concentration and sample orientation. Doublons are selected at low concentrations (low solutal undercooling) in contrast to the prediction of doublons at large thermal undercooling in pure materials. Doublons also exhibit preferred growth directions and changing the orientation of a specific doublonic grain changes the character and stability of the doublons. We observe transitions between seaweed and doublon growth with changes in concentration and sample orientation.
2005
Article
http://edoc.mpg.de/262252
info:doi/10.1103/PhysRevE.72.011601
Physical Review E, v.76, 011601-1-011601-6 (2005)
en
oai:edoc.mpg.de:2623492006-04-2043:960
Taking Wax for a Spin: Microplates in an Analog Model of Plate Tectonics
Katz, Richard F.
Bodenschatz, Eberhard
expertsonly
2005
Article
http://edoc.mpg.de/262349
Europhysics News, v.5, 155-158 (2005)
en
oai:edoc.mpg.de:2623542007-03-2843:960
A quantitative study of three-dimensional Lagrangian particle tracking algorithms
Ouellette, Nicholas T.
Xu, Haitao
Bodenschatz, Eberhard
expertsonly
A neural network particle finding algorithm and a new four-frame predictive tracking algorithm are proposed for three-dimensional Lagrangian particle tracking (LPT). A quantitative comparison of these and other algorithms commonly used in three-dimensional LPT is presented. Weighted averaging, one-dimensional and two-dimensional Gaussian fitting, and the neural network scheme are considered for determining particle centers in digital camera images. When the signal to noise ratio is high, the one-dimensional Gaussian estimation scheme is shown to achieve a good combination of accuracy and efficiency, while the neural network approach provides greater accuracy when the images are noisy. The effect of camera placement on both the yield and accuracy of three-dimensional particle positions is investigated, and it is shown that at least one camera must be positioned at a large angle with respect to the other cameras to minimize errors. Finally, the problem of tracking particles in time is studied. The nearest neighbor algorithm is compared with a three-frame predictive algorithm and two four-frame algorithms. These four algorithms are applied to particle tracks generated by direct numerical simulation both with and without a method to resolve tracking conflicts. The new four-frame predictive algorithm with no conflict resolution is shown to give the best performance. Finally, the best algorithms are verified to work in a real experimental environment.
2006
Article
http://edoc.mpg.de/262354
info:doi/1007/s00348-005-0068-7
Experiments in Fluids, v.40, 301-313 (2006)
en
oai:edoc.mpg.de:2623592007-03-2843:960
High Order Lagrangian Velocity Statistics in Turbulence
Xu, Haitao
Bourgoin, Mickaël
Ouellette, Nicholas T.
Bodenschatz, Eberhard
expertsonly
We report measurements of the Lagrangian velocity structure functions of orders 1 through 10 in a high Reynolds number (Taylor microscale Reynolds numbers of up to R(lambda) = 815 ) turbulence experiment. Passive tracer particles are tracked optically in three dimensions and in time, and velocities are calculated from the particle tracks. The structure function anomalous scaling exponents are measured both directly and using extended self-similarity and are found to be more intermittent than their Eulerian counterparts. Classical Kolmogorov inertial range scaling is also found for all structure function orders at times that trend downward as the order increases. The temporal shift of this classical scaling behavior is observed to saturate as the structure function order increases at times shorter than the Kolmogorov time scale.
2006
Article
http://edoc.mpg.de/262359
info:doi/10.1103/PhysRevLett.96.024503
Physical Review Letters, v.96, 024503-1-024503-4 (2006)
en
oai:edoc.mpg.de:2623662006-04-2043:960
On the distribution of Lagrangian accelerations in turbulent flows
Reynolds, A. M.
Mordant, N.
Crawford, A. M.
Bodenschatz, E.
expertsonly
Superstatistical Lagrangian stochastic models are shown to predict accurately the distribution of the magnitude of the acceleration vector in three-dimensional high Reynolds-number turbulence. Distributions are closely log-normal having high tails that are nearly coincident with measured distributions of enstrophy. The findings support the view that the dominant contribution to extreme accelerations comes from centripetal accelerations induced by vortex filaments.
2005
Article
http://edoc.mpg.de/262366
info:doi/10.1088/1367-2630/7/1/058
New Journal of Physics, v.7, 58-1-58-9 (2005)
en
oai:edoc.mpg.de:2646602006-04-2443:960
Multifractal Dimension of Lagrangian Turbulence
Xu, Haitao
Ouellette, Nicholas T.
Bodenschatz, Eberhard
expertsonly
We report experimental measurements of the Lagrangian multifractal dimension spectrum in an intensely turbulent laboratory water flow by the optical tracking of tracer particles. The Legendre transform of the measured spectrum is compared with measurements of the scaling exponents of the Lagrangian velocity structure functions, and excellent agreement between the two measurements is found, in support of the multifractal picture of turbulence. These measurements are compared with three model dimension spectra. When the nonexistence of structure functions of order less than -1 is accounted for, the models are shown to agree well with the measured spectrum.
2006
Article
http://edoc.mpg.de/264660
info:doi/10.1103/PhysRevLett.96.114503
Physical Review Letters, v.96, 114503-1-114503-4 (2006)
oai:edoc.mpg.de:2808342007-03-2843:960
Recombination of ozone via the chaperon mechanism
Ivanov, M. V.
Schinke, R.
expertsonly
2006
Article
http://edoc.mpg.de/280834
Journal of Chemical Physics, v.124, 104303-1-104303-10 (2006)
en
oai:edoc.mpg.de:2808402007-03-2843:960
Absorption spectrum and assignment of the Chappuis band of ozone
Grebenshchikov, S. Y.
Schinke, R.
Qu, Z.-W.
Zhu, H.
expertsonly
2006
Article
http://edoc.mpg.de/280840
Journal of Chemical Physics, v.124, 204313-1-204313-13 (2006)
en
oai:edoc.mpg.de:2808422007-03-2843:960
Dynamical studies of the ozone isotope effect: A status report
Schinke, R.
Grebenshchikov, S. Y.
Ivanov, M. V.
Fleurat-Lessard, P.
expertsonly
2006
Article
http://edoc.mpg.de/280842
Annuals Review of Physical Chemistry, v.57, 625-661 (2006)
en
oai:edoc.mpg.de:2808432007-03-2843:960
The photodissociation of ozone in the Hartley band: A theoretical analysis
Qu, Z.-W.
Zhu, H.
Grebenshchikov, S. Y.
Schinke, R.
expertsonly
2005
Article
http://edoc.mpg.de/280843
Journal of Chemical Physics, v.123, 074305-1-074305-12 (2005)
en
oai:edoc.mpg.de:2808442007-03-2843:960
Infrared spectrum of cyclic ozone: A theoretical investigation
Qu, Z.-W.
Zhu, H.
Schinke, R.
expertsonly
2005
Article
http://edoc.mpg.de/280844
Journal of Chemical Physics, v.123, 204324-1-204324-7 (2005)
en
oai:edoc.mpg.de:2808462007-03-2843:960
The Huggins band of ozone: Assignment of hot bands
Zhu, W.
Qu, Z.-W.
Grebenshchikov, S. Y.
Schinke, R.
Malicet, J.
Brion, J.
Daumont, D.
expertsonly
2005
Article
http://edoc.mpg.de/280846
Journal of Chemical Physics, v.122, 024310-1-024310-8 (2005)
en
oai:edoc.mpg.de:2814022007-03-2943:960
Nonlinear elastic polymers in random flow
Martins Afonso, M.
Vincenzi, D.
expertsonly
Polymer stretching in random smooth flows is investigated within the framework of the FENE dumbbell model. The advecting flow is Gaussian and short-correlated in time. The stationary probability density function of polymer extension is derived exactly. The characteristic time needed for the system to attain the stationary regime is computed as a function of the Weissenberg number and the maximum length of polymers. The transient relaxation to the stationary regime is predicted to be exceptionally slow in the proximity of the coil-stretch transition.
2005
Article
http://edoc.mpg.de/281402
info:doi/10.1017/S0022112005005951
Journal of Fluid Mechanics, v.540, 99-108 (2005)
en
oai:edoc.mpg.de:2814032006-07-1243:960
Asymmetry-induced particle drift in a rotational flow
Bluemink, J. J.
van Nierop, E. A.
Luther, S.
Deen, N. G.
Magnaudet, J.
Prosperetti, A.
Lohse, D.
expertsonly
We report on an intriguing phenomenon taking place in a liquid rotating around a fixed horizontal axis. Under suitable conditions, bubbles and particles are observed to drift along the axis of rotation maintaining a constant distance from it and a constant angle of elevation above the horizontal. Absence of fore-aft symmetry of the bubble or particle shape is a prerequisite for this phenomenon. For bubbles, this requires a volume sufficiently large for surface-tension effects to be small and large deformations to be possible. Particle image velocimetry and flow visualization suggest that the wake does not play a role. The dependence on bubble radius, particle shape, liquid viscosity, and speed of rotation is investigated.
2005
Article
http://edoc.mpg.de/281403
info:doi/10.1063/1.1978921
Physics of Fluids, v.17, 072106-1-072106-5 (2005)
oai:edoc.mpg.de:2814042006-07-1243:960
Bubble shape and orientation determination with a four-point optical fibre probe
Guet, S.
Luther, S.
Ooms, G.
expertsonly
We propose a new method to estimate the aspect ratio and orientation of bubbles by using their time series obtained with a four-point optical-fibre probe. The feasibility and accuracy of the method was first analysed by using synthetic bubble–probe interaction data and single bubble experiments in pure water. Reasonable comparisons between this new technique and image analysis results were obtained. As a next step, the technique is applied to a vertical bubbly pipe flow at high void fraction. The typical bubble spherical equivalent diameter is 2–8 mm. The results provided by these measurements are compared with an available bubble aspect ratio correlation. A reasonable agreement is found. Some first results about the bubble orientation changes with bubble shape in bubbly shear flows are also presented.
2005
Article
http://edoc.mpg.de/281404
info:doi/10.1016/j.expthermflusci.2005.03.007
Experimental Thermal and Fluid Science, v.29, 803-812 (2005)
oai:edoc.mpg.de:2814052006-07-1243:960
Data analysis for hot-film anemometry in turbulent bubbly flow
Luther, Stefan
Rensen, Judith
van den Berg, Thomas H.
Lohse, Detlef
expertsonly
We report on a new method for the analysis of hot-film anemometry in turbulent bubbly flows based on stochastic pattern recognition summarizing our results of [J.M. Rensen, S. Luther, J. de Vries, D. Lohse, Hot-film anemometry in bubbly flow I: bubble–probe interaction, in press; S. Luther, J. Rensen, Hot-film anemometry in bubbly flow II: local phase discrimination, in press; J.M. Rensen, S. Luther, D. Lohse, Velocity structure functions in turbulent two-phase flows, J. Fluid Mech., in press]. It consists of an optimal signal decomposition using an adaptive wavelet transform and neural network based classification. We discuss the application of autoregressive models to obtain energy spectra for gapped time series.
2005
Article
http://edoc.mpg.de/281405
info:doi/10.1016/j.expthermflusci.2005.03.016
Experimental Thermal and Fluid Science, v.29, 821-826 (2005)
oai:edoc.mpg.de:2814062006-07-1343:960
Full-field correlation-based image processing for PIV
Nobach, Holger
Ouellette, Nicholas T.
Bodenschatz, Eberhard
Tropea, C.
expertsonly
Due to its high robustness, correlation-based particle image velocimetry (PIV) has become the prime choice for processing image-based flow measurements in fluid dynamics experiments. However, in recent years, whole-field techniques like optical flow methods have been successfully applied to this kind of images. To avoid the dependence of optical flow methods on intensity variations and to combine the robustness of the correlation-based PIV technique with the whole-field flow description of the optical flow method, a hybrid estimation procedure has been developed. It is an iterative method, optimizing a dense, hypothetical velocity field with respect to vanishing residual displacements, obtained by image correlation.
M. Gharib
2005
Proceedings
http://edoc.mpg.de/281406
oai:edoc.mpg.de:2814072006-07-1243:960
Hot-film anemometry in bubbly flow I: bubble–probe interaction
Rensen, Judith
Luther, Stefan
de Vries, Joris
Lohse, Detlef
expertsonly
Hot-film anemometry; Bubbly flow; Bubble–probe interaction
The interaction between a bubble, which is rising in a descending water flow, and a hot-film anemometer was experimentally investigated using stereoscopic high-speed imaging. The mean downward water velocity varied from 0 up to 0.15 m/s, i.e., relatively low, allowing for an extended bubble–probe interaction. Moreover, the direction of the water causes the wake of the probe to play a role before the bubble touches the probe. The equivalent bubble radii were 0.4–2.8 mm and the bubble velocities relative to the probe ranged from 0.04 to 0.38 m/s. Image processing techniques were applied to reconstruct the bubbles’ path, shape, and orientation during the interaction process. As a result, three types of interactions were found, namely penetrating, bouncing, and splitting interactions. The image sequences were compared with the corresponding time series of the hot-film anemometer. From the time series the type of interaction cannot be deduced, at least not for the analyzed flow situation. Furthermore, we demonstrated that the residence time estimate from the hot-film data is systematically biased in our type of experiments. Finally, it was found that the velocity of a bubble may be altered considerably due to the interaction.
2005
Article
http://edoc.mpg.de/281407
info:doi/10.1016/j.ijmultiphaseflow.2004.11.005
International Journal of Multiphase Flow, v.31, 285-301 (2005)
oai:edoc.mpg.de:2814082012-02-2143:960
The effect of bubbles on developed turbulence
Rensen, Judith
Luther, Stefan
Lohse, Detlef
expertsonly
Hot-film anemometry measurements are performed in a fully developed turbulent bubbly flow. For the bubble detection in the signal, both a threshold method and a new pattern recognition algorithm are employed. The measurements are carried out with gas fractions up to 3% and a mean water velocity of 0.20 m s-1, corresponding to a Reynolds number of about 9x10 4. The typical bubble radius is 1–2 mm, corresponding to 10–20 Kolmogorov length scales. In this regime, a ‘bubblance’ parameter b which compares the kinetic energy originating from the rising bubbles with that of the turbulence fluctuations is smaller than 1. Probability distribution functions, structure functions (with and without the extended self-similarity (ESS) method), and spectra of the water velocity time series are calculated. Both our results for the turbulent energy spectra and the second-order structure functions show qualitative agreement with numerical results by Massitelli, Lohse & Toschi (Phys. Fluids, vol. 15 (2003), p. L5), i.e. a more pronounced energy enhancement on small scales than on large scales owing to the presence of bubbles, leading to a less steep slope in the spectrum as compared to the Kolmogorov -5/3 law. These results are robust, i.e. do not depend on details of the bubble detection scheme.
2005
Article
http://edoc.mpg.de/281408
info:doi/10.1017/S0022112005005276
Journal of Fluid Mechanics, v.538, 153-187 (2005)
oai:edoc.mpg.de:2814092006-07-1243:960
Drag Reduction in Bubbly Taylor-Couette Turbulence
van den Berg, Thomas H.
Luther, Stefan
Lathrop, Daniel P.
Lohse, Detlef
expertsonly
In Taylor-Couette flow the total energy dissipation rate and therefore the drag can be determined by measuring the torque on the system. We do so for Reynolds numbers between Re = 7×10 4 and Re = 10 6 after having injected (i) small bubbles (R = 1 mm) up to a volume concentration of α=5% and (ii) buoyant particles (ρp/ρl = 0.14) of comparable volume concentration. In case (i) we observe a crossover from little drag reduction at smaller Re to strong drag reduction up to 20% at Re = 10 6. In case (ii) we observe at most little drag reduction throughout. Several theoretical models for bubbly drag reduction are discussed in view of our findings.
2005
Article
http://edoc.mpg.de/281409
info:doi/10.1103/PhysRevLett.94.044501
Physical Review Letters, v.94, 044501-1-044501-4 (2005)
oai:edoc.mpg.de:2814102006-07-1243:960
Transitions to Electrochemical Turbulence
Varela, Hamilton
Beta, Carsten
Bonnefont, Antoine
Krischer, Katharina
expertsonly
We report experimental evidence of transitions from limit cycle oscillations through a phase turbulent regime to space-time defect turbulence in a spatially (quasi-)one-dimensional electrochemical system with nonlocal coupling. The transitions are characterized in terms of the defect density, the Karhunen-Loève decomposition dimension, and a measure of the degree of spatial correlation in the data. Furthermore, these quantities give the first experimental confirmation that the spatial coupling range in electrochemical systems indeed depends on the distance between the working and the counterelectrode.
2005
Article
http://edoc.mpg.de/281410
info:doi/10.1103/PhysRevLett.94.174104
Physical Review Letters, v.94, 174104-1-174104-4 (2005)
oai:edoc.mpg.de:2814112007-03-2843:960
A hierarchy of global coupling induced cluster patterns during the oscillatory H2-electrooxidation reaction on a Pt ring-electrode
Varela, Hamilton
Beta, Carsten
Bonnefont, Antoine
Krischer, Katharina
expertsonly
We report experimental results on spatiotemporal pattern formation during the oscillatory hydrogen electrooxidation reaction on a Pt ring-electrode under negative (desynchronizing) global coupling (GC). Spatially one-dimensional profiles of the interfacial potential drop along the angular direction of the ring electrode are recorded by means of a potential probe. The dynamics is investigated as a function of two control parameters, the applied voltage U and the strength of the global coupling. The latter is adjusted either by varying the distance between the working electrode (WE) and the reference electrode (RE) or by inserting a negative impedance device in series with the WE. In the absence of global coupling, uniform oscillations were destabilized by migration coupling, and electrochemical turbulence developed at large values of U (H. Varela, C. Beta, A. Bonnefont and K. Krischer, Phys. Rev. Lett., 2005, 94, 174104; ref. 1). Already low global coupling strengths sufficed to suppress turbulence. Instead, regular two-phase clusters formed. At higher coupling strength, a second type of two-phase cluster was observed as well as two types of irregular cluster patterns, which were connected with an irregular motion of the cluster boundaries and the emergence and disappearance of clusters through splitting and merging of the boundaries, respectively. Upon increasing the coupling strength even further, five-phase clusters were stabilized and at the highest coupling strength applied the cluster patterns transformed into strongly modulated pulses. The two types of two-phase clusters and the five-phase clusters are analyzed employing several signal processing techniques.
2005
Article
http://edoc.mpg.de/281411
info:doi/10.1039/b502027a
Physical Chemistry Chemical Physics, v.7, 2429-2439 (2005)
oai:edoc.mpg.de:3073522007-03-2843:960
The Role of Pair Dispersion in Turbulent Flow
Bourgoin, Mickael
Ouellette, Nicholas T.
Xu, Haitao
Berg, Jacob
Bodenschatz, Eberhard
popular
Mixing and transport in turbulent flows—which have strong local concentration fluctuations—are essential in many natural and industrial systems including reactions in chemical mixers, combustion in engines and burners, droplet formation in warm clouds, and biological odor detection and chemotaxis. Local concentration fluctuations, in turn, are intimately tied to the problem of the separation of pairs of fluid elements. We have measured this separation rate in an intensely turbulent laboratory flow and have found, in quantitative agreement with the seminal predictions of Batchelor, that the initial separation of the pair plays an important role in the subsequent spreading of the fluid elements. These results have surprising consequences for the decay of concentration fluctuations and have applications to biological and chemical systems.
2006
Article
http://edoc.mpg.de/307352
info:doi/10.1126/science.1121726
Science, v.311, 835-838 (2006)
en
oai:edoc.mpg.de:3074172007-03-2843:960
Small-scale anisotropy in Lagrangian turbulence
Ouellette, Nicholas T.
Xu, Haitao
Bourgoin, Mickael
Bodenschatz, Eberhard
expertsonly
We report measurements of the second-order Lagrangian structure function and the Lagrangian velocity spectrum in an intensely turbulent laboratory flow. We find that the asymmetries of the large-scale flow are reflected in the small-scale statistics. In addition, we present new measurements of the Lagrangian structure function scaling constant C0, which is of central importance to stochastic turbulence models as well as to the understanding of turbulent pair dispersion and scalar mixing. The scaling of C0 with the turbulence level is also investigated, and found to be in agreement with an existing model.
2006
Article
http://edoc.mpg.de/307417
info:doi/10.1088/1367-2630/8/6/102
New Journal of Physics, v.8, 102-1-102-10 (2006)
en
oai:edoc.mpg.de:3074592007-03-2843:960
Dictyostelium discoideum chemotaxis: Threshold for directed motion
Song, Loling
Nadkarni, Sharvari M.
Bödeker, Hendrik U.
Beta, Carsten
Bae, Albert
Franck, Carl
Rappel, Wouter-Jan
Loomis, William F.
Bodenschatz, Eberhard
expertsonly
Chemotaxis; Dictyostelium discoideum; Microfluidics
The chemotactic response of Dictyostelium discoideum cells to stationary, linear gradients of cyclic adenosine 3′,5′-monophosphate (cAMP) was studied using microfluidic devices. In shallow gradients of less than 10−3 nM/μm, the cells showed no directional response and exhibited a constant basal motility. In steeper gradients, cells moved up the gradient on average. The chemotactic speed and the motility increased with increasing steepness up to a plateau at around 10−1 nM/μm. In very steep gradients, above 10 nM/μm, the cells lost directionality and the motility returned to the sub-threshold level. In the regime of optimal response the difference in receptor occupancy at the front and back of the cell is estimated to be only about 100 molecules.
2006
Article
http://edoc.mpg.de/307459
info:doi/10.1016/j.ejcb.2006.01.012
European Journal of Cell Biology, v.85, 981-989 (2006)
oai:edoc.mpg.de:3075282007-03-2843:960
Lagrangian Measurements of Inertial Particle Accelerations in Grid Generated Wind Tunnel Turbulence
Ayyalasomayajula, S.
Gylfason, A.
Collins, L. R.
Bodenschatz, E.
Warhaft, Z.
expertsonly
We describe Lagrangian measurements of water droplets in grid generated wind tunnel turbulence at a Taylor Reynolds number of Rλ= 250 and an average Stokes number (St) of approximately 0.1. The inertial particles are tracked by a high speed camera moving along the side of the tunnel at the mean flow speed. The standardized acceleration probability density functions of the particles have spread exponential tails that are narrower than those of a fluid particles (St ≈ 0) and there is a decrease in the acceleration variance with increasing Stokes number. A simple vortex model shows that the inertial particles selectively sample the fluid field and are less likely to experience regions of the fluid undergoing the largest accelerations. Recent direct numerical simulations compare favorably with these first measurements of Lagrangian statistics of inertial particles in highly turbulent flows.
2006
Article
http://edoc.mpg.de/307528
info:doi/10.1103/PhysRevLett.97.144507
Physical Review Letters, v.97, 144507-1-144507-4 (2006)
en
oai:edoc.mpg.de:3075752007-03-2843:960
An experimental study of turbulent relative dispersion models
Ouellette, Nicholas T.
Xu, Haitao
Bourgoin, Mickael
Bodenschatz, Eberhard
expertsonly
We report measurements of the spreading rate of pairs of tracer particles in an intensely turbulent laboratory water flow. We compare our measurements of this turbulent relative dispersion with the longstanding work of Richardson and Batchelor, and find excellent agreement with Batchelor's predictions. The distance neighbour function, the probability density function of the relative dispersion, is measured and compared with existing models. We also investigate the recently proposed exit time analysis of relative dispersion.
2006
Article
http://edoc.mpg.de/307575
info:doi/doi:10.1088/1367-2630/8/6/109
New Journal of Physics, v.85, 109-1-109-23 (2006)
en
oai:edoc.mpg.de:3076642007-03-2843:960
Single polymer dynamics in elongational flow and the confluent Heun equation
Vincenzi, Dario
Bodenschatz, Eberhard
expertsonly
We investigate the non-equilibrium dynamics of an isolated polymer in a stationary elongational flow. We compute the relaxation time to the steady-state configuration as a function of the Weissenberg number. A strong increase of the relaxation time is found around the coil–stretch transition, which is attributed to the large number of polymer configurations. The relaxation dynamics of the polymer is solved analytically in terms of a central two-point connection problem for the singly confluent Heun equation.
2006
Article
http://edoc.mpg.de/307664
info:doi/10.1088/0305-4470/39/34/007
Journal of Physics A: Mathematical and General, v.39, 10691-10701 (2006)
en
oai:edoc.mpg.de:3076652007-03-2843:960
Magnetic field transport and kinematic dynamo effect: a Lagrangian interpretation
Celani, A.
Mazzino, A.
Vincenzi, D.
expertsonly
dynamo effect, Lagrangian dynamics, statistical conservation laws
The growth of magnetic fluctuations in the inertial range of turbulence is investigated in terms of fluid particle dynamics. The existence of dynamo effect is related to the time behaviour of the correlations between tangent vectors evolving along Lagrangian trajectories. In the presence of dynamo effect, the correlations between tangent vectors grow exponentially in time; in the absence of dynamo effect they decay as power laws. The above behaviours are intimately related to statistical conservation laws for the Lagrangian dynamics.
2006
Article
http://edoc.mpg.de/307665
info:doi/10.1098/rspa.2005.1561
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, v.462, 137-147 (2006)
en
oai:edoc.mpg.de:3076682007-03-2843:960
Viscosity Destabilizes Sonoluminescing Bubbles
Toegel, Ruediger
Luther, Stefan
Lohse, Detlef
expertsonly
In single-bubble sonoluminescence (SBSL) microbubbles are trapped in a standing sound wave, typically in water or water-glycerol mixtures. However, in viscous liquids such as glycol, methylformamide, or sulphuric acid it is not possible to trap the bubble in a stable position. This is very peculiar as larger viscosity normally stabilizes the dynamics. Suslick and co-workers call this new mysterious state of SBSL "moving-SBSL." We identify the history force (a force nonlocal in time) as the origin of this destabilization and show that the instability is parametric. A force balance model quantitatively accounts for the observed quasiperiodic bubble trajectories.
2006
Article
http://edoc.mpg.de/307668
info:doi/10.1103/PhysRevLett.96.114301
Physical Review Letters, 114301-1-114301-4 (2006)
en
oai:edoc.mpg.de:3076702007-03-2943:960
Energy spectra in microbubbly turbulence
van den Berg, Thomas H.
Luther, Stefan
Lohse, Detlef
expertsonly
Microbubbles (R0=100 µm) are injected in fully developed turbulence (Reλ=200) up to a volume concentration of 0.3%. An enhancement of the energy on small scales and a reduction on the large scales is observed, confirming theoretical prediction by I. Mazzitelli, D. Lohse, and F. Toschi [Phys. Fluids 15, L5 (2003)]. The result is a (nonuniversal) less steep slope than –5/3 in the power spectrum.
2006
Article
http://edoc.mpg.de/307670
info:doi/10.1063/1.2185688
Physics of Fluids, v.18, 038103-1-038103-3 (2006)
en
oai:edoc.mpg.de:3076712007-03-2843:960
Defect-mediated turbulence in a catalytic surface reaction
Beta, C.
Mikhailov, A. S.
Rotermund, H. H.
Ertl, G.
expertsonly
We analyze the statistical properties of topological defects in an experimental reaction-diffusion system—the catalytic CO oxidation on Pt(110). Based on the gain and loss rates of defects, a probabilistic description of defect-mediated turbulence in this system is derived. We observe deviations from theoretical predictions for the statistics of topological defects that can be explained by the presence of short-range correlations between defects and underline the importance of correlations for defect dynamics in such systems.
2006
Article
http://edoc.mpg.de/307671
info:doi/10.1209/epl/i2006-10215-5
Europhysics Letters, v.75, 868-874 (2006)
en
oai:edoc.mpg.de:3076722007-03-2943:960
Turbulent bubbly flow
van den Berg, Thomas H.
Luther, Stefan
Mazzitelli, Irene M.
Rensen, Judith M.
Toschi, Federico
Lohse, Detlef
expertsonly
The effect of bubbles on fully developed turbulent flow is investigated numerically and experimentally, summarizing the results of our previous papers (Mazzitelli et al., 2003, Physics of Fluids15, L5. and Journal of Fluid Mechanics 488, 283; Rensen, J. et al. 2005, Journal of Fluid Mechanics 538, 153). On the numerical side, we simulate Navier–Stokes turbulence with a Taylor–Reynolds number of Reλ ≈ 60, a large large-scale forcing, and periodic boundary conditions. The point-like bubbles follow their Lagrangian paths and act as point forces on the flow. As a consequence, the spectral slope is less steep as compared to the Kolmogorov case. The slope decrease is identified as a lift force effect. On the experimental side, we do hot-film anemometry in a turbulent water channel with Reλ ≈ 200 in which we have injected small bubbles up to a volume percentage of 3%. Here the challenge is to disentangle the bubble spikes from the hot-film velocity signal. To achieve this goal, we have developed a pattern recognition scheme. Furthermore, we injected microbubbles up to a volume percentage of 0.3%. Both in the counter flowing situation with small bubbles and in the co-flow situation with microbubbles, we obtain a less spectral slope, in agreement with the numerical result.
2006
Article
http://edoc.mpg.de/307672
info:doi/10.1080/14685240500460782
urn:ISSN:1468-5248
Journal of Turbulence, v.7, 1-12 (2006)
en
oai:edoc.mpg.de:3076732007-03-3043:960
Neue Auflösungsgrenzen von PIV
Nobach, Holger
Bodenschatz, Eberhard
expertsonly
Physikalisch-Technische Bundesanstalt Braunschweig
2006
Conference-Paper
http://edoc.mpg.de/307673
urn:ISBN:3-9805613-3-X
Proceedings der 14. GALA-Fachtagung "Lasermethoden in der Strömungsmesstechnik", Physikalisch-Technische Bundesanstalt Braunschweig, 4.1-4.8 (2006)
de
oai:edoc.mpg.de:3076742007-03-3043:960
Messung Lagrange'scher Beschleunigungen mittels Laser-Doppler-Anemometrie
Kinzel, M.
Nobach, H.
Tropea, C.
Bodenschatz, E.
expertsonly
Physikalisch-Technische Bundesanstalt Braunschweig
2006
Conference-Paper
http://edoc.mpg.de/307674
urn:ISBN:3-9805613-3-X
Proceedings der 14. GALA-Fachtagung "Lasermethoden in der Strömungsmesstechnik", Physikalisch-Technische Bundesanstalt Braunschweig, 1.1-1.8 (2006)
de
oai:edoc.mpg.de:3076752007-03-3043:960
New Resolution limits in PIV image processing
Nobach, H.
Bodenschatz, E.
expertsonly
2006
Conference-Paper
http://edoc.mpg.de/307675
13th International Symposium Lisbon (2006)
en
oai:edoc.mpg.de:3076762007-03-2943:960
Spin-orbit mechanism of predissociation in the Wulf band of ozone
Grebenshchikov, S. Y.
Qu, Z.-W.
Zhu, H.
Schinke, R.
expertsonly
ozone; predissociation; vibrational states; spin-orbit interactions; ground states; ab initio calculations
Previously calculated resonance widths of the ground vibrational levels in the electronic states 1 3A" (3A2) and 1 3A' (3B2), which belong to the Wulf band system of ozone, are significantly smaller than observed experimentally. We demonstrate that predissociation is drastically enhanced by spin-orbit coupling between 1 3A"/X 1A' and 1 3A'/1 3A". Multistate quantum mechanical calculations using ab initio spin-orbit coupling matrix elements give linewidths of optically bright components of the right order of magnitude.
2006
Article
http://edoc.mpg.de/307676
info:doi/10.1063/1.2219444
The Journal of Chemical Physics, v.125, 021102-1-021102-4 (2006)
en
oai:edoc.mpg.de:3076772007-03-2943:960
Reaction paths and elementary bifurcations tracks: The diabatic 1B2-state of ozone
Farantos, S. C.
Qu, Z.-W.
Zhu, H.
Schinke, R.
expertsonly
bifurcation theory; periodic orbits; classical and quantum molecular dynamics
Bifurcations of equilibrium points and periodic orbits are common in nonlinear dynamical systems when some parameters change. The vibrational motions of a molecule are nonlinear, and the bifurcation phenomena are seen in spectroscopy and chemical reactions. Bifurcations may lead to energy localization in speciﬁc bonds, and thus, they have important consequences for elementary chemical reactions, such as isomerization and dissociation/association. In this article we investigate how elementary bifurcations, such as saddle-node and pitchfork bifurcations, appear in small molecules and show their manifestations in the quantum mechanical frequencies and in the topology of wave functions. We present the results of classical and quantum mechanical calculations on a new (diabatic) potential energy surface of ozone for the 1B2 state. This excited electronic state of ozone is pertinent for the absorption of the harmful UV radiation from the sun. We demonstrate that regular localized overtone states, which extend from the bottom of the well up to the dissociation or isomerization barrier, are associated with families of periodic orbits emanated from elementary bifurcations.
2006
Article
http://edoc.mpg.de/307677
info:doi/10.1142/S0218127406015799
International Journal of Bifurcation and Chaos, v.16, 1913-1928 (2006)
en
oai:edoc.mpg.de:3076782007-03-2943:960
Energies and spatial features for the rotationless bound states of 4He3+ (2Σg+): A cationic core from helium cluster ionization
Scifoni, E.
Gianturco, F. A.
Grebenshchikov, S. Y.
Schinke, R.
expertsonly
helium ions; positive ions; atomic clusters; ionisation; ab initio calculations; potential energy surfaces; ground states; vibrational states; molecular configurations; wave functions; bound states
Ab initio quantum calculations have been carried out on the helium ionic trimer. The potential energy surface is accurately fitted, especially in the vicinity of the three equivalent minima. The spectrum of bound states for the zero angular momentum is computed and analyzed in detail. Energies and wave functions reveal several interesting features related to the fact that He3+ represents one of the few homonuclear ionic trimers that are linear in their ground vibrational state. At low energies, the triply degenerate eigenfunctions are localized at the potential minimum. With growing excitation energy, however, the wave functions exhibit stronger spatial delocalization.
2006
Article
http://edoc.mpg.de/307678
info:doi/10.1063/1.2358986
The Journal of Chemical Physics, v.125, 164304-1-164304-9 (2006)
en
oai:edoc.mpg.de:3076792007-03-3043:960
Measurement of Lagrangian acceleration using the laser Doppler technique
Kinzel, M.
Nobach, H.
Tropea, C.
Bodenschatz, E.
expertsonly
2006
Conference-Paper
http://edoc.mpg.de/307679
13th International Symposium Lisbon (2006)
en
oai:edoc.mpg.de:3099192007-03-2943:960
Dynamical Slowdown of Polymers in Laminar and Random Flows
Celani, A.
Puliafito, A.
Vincenzi, D.
expertsonly
The influence of an external flow on the relaxation dynamics of a single polymer is investigated theoretically and numerically. We show that a pronounced dynamical slowdown occurs in the vicinity of the coil-stretch transition, especially when the dependence on polymer conformation of the drag is accounted for. For the elongational flow, relaxation times are exceedingly larger than the Zimm relaxation time, resulting in the observation of conformation hysteresis. For random smooth flows, hysteresis is not present. Yet, relaxation dynamics is significantly slowed down because of the large variety of accessible polymer configurations. The implications of these results for the modeling of dilute polymer solutions in turbulent flows are addressed.
2006
Article
http://edoc.mpg.de/309919
info:doi/10.1103/PhysRevLett.97.118301
Physical Review Letters, v.97, 118301-1-118301-4 (2006)
en
oai:edoc.mpg.de:3503352008-03-2043:960
Flow Photolysis for Spatiotemporal Stimulation of Single Cells
Beta, Carsten
Wyatt, Danica
Rappel, Wouter-Jan
Bodenschatz, Eberhard
expertsonly
Quantitative studies of cellular systems require experimental techniques that can expose single cells to well-controlled chemical stimuli with high spatiotemporal resolution. Here, we combine microfluidic techniques with the photochemical release of caged signaling molecules to generate tailored stimuli on the length scale of individual cells with subsecond switching times. We exemplify this flexible approach by initiating membrane translocation of fluorescent fusion proteins in chemotactic Dictyostelium discoideum cells.
2007
Article
http://edoc.mpg.de/350335
urn:ISSN:00032700
Analytical Chemistry, v.79, 3940-3944 (2007)
en
oai:edoc.mpg.de:3503382008-03-2043:960
High Frequency Periodic Forcing of the Oscillatory Catalytic CO Oxidation on Pt (110)
Bodega, P. S.
Kaira, P.
Beta, Carsten
Krefting, D.
Bauer, D.
Mirwald-Schulz, B.
Punckt, Christian
Rotermund, H. H.
expertsonly
Resonant periodic forcing is applied to catalytic CO oxidation on platinum (110) in the oscillatory regime. The external parameters are chosen such that the unperturbed system spontaneously develops chemical turbulence. By periodically modulating the CO partial pressure, changes in the spatiotemporal behaviour of the system can be induced: the turbulent behaviour is suppressed and frequency locked patterns with sub-harmonic entrainment develop. A novel gas-driving compressor has been implemented to perform the experimental work.
2007
Article
http://edoc.mpg.de/350338
info:doi/10.1088/1367-2630/9/3/061
New Journal of Physics, v.9, 61-1-61-18 (2007)
en
oai:edoc.mpg.de:3503502008-03-2543:960
Exploring Renner-Teller induced quenching in the reaction
H(2S) + NH(a1∆): A combined experimental and theoretical study
Adam, Lutz
Hack, Walter
Mcbane, George C.
Zhu, Hui
Qu, Zheng-Wang
Schinke, Reinhard
expertsonly
2007
Article
http://edoc.mpg.de/350350
Journal of Chemical Physics, v.126, 034304-1-034304-13 (2007)
en
oai:edoc.mpg.de:3503552008-03-2643:960
Grenzen von PIV durch individuelle Intensitätsänderung von Streuteilchen
Nobach, Holger
Bodenschatz, Eberhard
expertsonly
2007
Conference-Paper
http://edoc.mpg.de/350355
15. Fachtagung "Lasermethoden in der Strömungsmesstechnik", 11.1-11.8 (2007)
de
oai:edoc.mpg.de:3503572008-03-2643:960
Limitations of Accuracy in PIV due to Individual Variations of Particle Image Intensities
Nobach, Holger
Bodenschatz, Eberhard
expertsonly
2007
Conference-Paper
http://edoc.mpg.de/350357
PIV 2007, 1-15 (2007)
en
oai:edoc.mpg.de:3504532008-03-2043:960
Measuring Lagrangian Statistics in Intense Turbulence
Ouellette, Nicholas T.
Xu, Haitao
Bodenschatz, Eberhard
expertsonly
Springer-Verlag
2007
InBook
http://edoc.mpg.de/350453
Springer Handbook of Experimental Fluid Dynamics, 789-799 (2007)
en
oai:edoc.mpg.de:3504972008-03-2043:960
Wave Emission from Heterogeneities Opens a Way to Controlling Chaos in the Heart
Pumir, Alain
Nikolski, V.
Hörning, M.
Isomura, A.
Agladze, K.
Yoshikawa, K.
Gilmour, Robert
Bodenschatz, Eberhard
Krinsky, Valentin
expertsonly
The effectiveness of chaos control in large systems increases with the number of control sites. We find that electric field induced wave emission from heterogeneities (WEH) in the heart gives a unique opportunity to have as many control sites as needed. The number of pacing sites grows with the amplitude of the electric field. We demonstrate that WEH has important advantages over methods used in clinics, and opens a new way to manipulate vortices in experiments, and potentially to radically improve the clinical methods of chaos control in the heart.
2007
Article
http://edoc.mpg.de/350497
info:doi/10.1103/PhysRevLett.99.208101
Physical Review Letters, v.99, 208101-1-208101-4 (2007)
en
oai:edoc.mpg.de:3505212008-03-2043:960
Formation and Stability of Band Patterns in a Rotating Suspension-Filled Cylinder
Seiden, Gabriel
Ungarish, M.
Lipson, Stephen G.
expertsonly
We explore the phenomenon of segregation and pattern formation in the complex system of a rotating horizontal cylinder completely filled with a dilute suspension of non-Brownian particles. A general dimensionless analysis is presented, which reveals the importance of the different dimensionless parameters involved. A detailed account of the mechanism of segregation and formation of axial bands for the case of low viscosity fluids is given. According to the analysis the axial pressure gradient associated with an inertial-mode excitation within the bounded fluid is responsible for the formation of bands in interleaving nodal planes of the excitation. The question of stability of the band patterns is addressed and a phase diagram in the appropriate dimensionless space is presented.
2007
Article
http://edoc.mpg.de/350521
info:doi/10.1103/PhysRevE.76.026221
Physical Review E, v.76, 026221-1-026221-9 (2007)
en
oai:edoc.mpg.de:3505252008-03-2643:960
Application of Laser Doppler Velocity Profile Sensor to Turbulent Flows: Measurement of Water Channel Flow and Two-Point Correlation
Shirai, K.
Bayer, C.
Nobach, Holger
Klaucke, C.
Voigt, H.
Büttner, L.
Czarske, J.
expertsonly
2007
Conference-Paper
http://edoc.mpg.de/350525
Lasermethoden in der Strömungsmesstechnik, 3.1-3.6 (2007)
en
oai:edoc.mpg.de:3505272008-03-2043:960
Stretching of Polymers in Isotropic Turbulence: A Statistical Closure
Vincenzi, Dario
Jin, Shi
Bodenschatz, Eberhard
Collins, Lance R.
expertsonly
We present a new closure for the mean rate of stretching of a dissolved polymer by homogeneous isotropic turbulence. The polymer is modeled by a bead-spring-type model (e.g., Oldroyd B, FENE-P, Giesekus) and the analytical closure is obtained assuming the Lagrangian velocity gradient can be modeled as a Gaussian, white-noise stochastic process. The resulting closure for the mean stretching depends upon the ratio of the correlation time for strain and rotation. Additionally, we derived a second-order expression for circumstances when strain and rotation have a finite correlation time. Finally, the base level closure is shown to reproduce results from direct numerical simulations by simply modifying the coefficients.
2007
Article
http://edoc.mpg.de/350527
info:doi/10.1103/PhysRevLett.98.024503
urn:ISSN:0031-9007
Physical Review Letters, v.98, 024503-1-024503-4 (2007)
en
oai:edoc.mpg.de:3505282008-03-2043:960
Statistical Closures for Homogeneous Shear Flow Turbulence of Dilute Polymer Solutions
Vincenzi, Dario
Jin, S.
Vaithianathan, T.
Collins, Lance R.
Bodenschatz, Eberhard
expertsonly
Springer
2007
InBook
http://edoc.mpg.de/350528
info:doi/10.1007/978-3-540-32603-8_53
urn:ISBN:978-3-540-32602-1 (Print) 978-3-540-32603-8 (Online)
Springer Proceedings in Physics, Progress in Turbulence II, Proceedings of the iTi Conference in Turbulence 2005, 261-264 (2007)
en
ResultSet_3uyLZIshF2N_range_100-199