Home News About Us Contact Contributors Disclaimer Privacy Policy Help FAQ

Home
Search
Quick Search
Advanced
Fulltext
Browse
Collections
Persons
My eDoc
Session History
Login
Name:
Password:
Documentation
Help
Support Wiki
Direct access to
document ID:


          Institute: MPI für Kernphysik     Collection: Physics of Atmospheric Molecular Processes     Display Documents



  history
ID: 61362.0, MPI für Kernphysik / Physics of Atmospheric Molecular Processes
Ion-induced aerosol formation: New insights from laboratory measurements of mixed cluster ions HSO4-(H2SO4)a(H2O)w and H+(H2SO4)a(H2O)w
Authors:Wilhelm, Stefan; Eichkorn, Sven; Wiedner, Dirk; Pirjola, Liisa; Arnold, Frank
Language:English
Date of Publication (YYYY-MM-DD):2004-04
Title of Journal:Atmospheric Environment
Volume:38
Issue / Number:12
Start Page:1735
End Page:1744
Review Status:not specified
Audience:Experts Only
Abstract / Description:Here we report on laboratory investigations of mixed cluster ions composed of sulfuric acid and water molecules HSO4-(H2SO4)a(H2O)w and H+(H2SO4)a(H2O)w. Such ions have potentially an important role in atmospheric H2SO4/H2O aerosol formation via ion induced nucleation. The investigations were made using a flow reactor equipped with two ion mass spectrometers which had either a high mass resolution but a relatively small mass range (0 - 750 amu) or a low mass resolution but a large mass range (0 - 10000 amu). Our experiments led to the following major findings: (a) Both negative and positive cluster ions take up H2SO4 molecules very efficiently. (b) For negative ions the sulfuric acid mole fraction is initially large, but as the ions grow, it rapidly approaches the value expected for neutral clusters. (c) For positive ions the sulfuric acid mole fraction is initially small, but as the ions grow, it rapidly increases and approaches the value expected for neutral clusters. (d) The measurements indicate that thermal detachment of sulfuric acid molecules from the cluster ions is important and strongly limits ion growth. The thermal detachment of sulfuric acid molecules is more efficient for positive ions compared to negative ions. Our experiments have interesting implications for ion induced nucleation of H2SO4/H2O in the atmosphere which are addressed.
Free Keywords:positive and negative ions, sulphuric acid mole fraction, growth of ions, homogeneous nucleation, ion-induced nucleation
External Publication Status:published
Document Type:Article
Affiliations:MPI für Kernphysik/Group K. Mauersberger/Atmospheric Trace Gas Environmental Physics (F. Arnold)
External Affiliations:University of Helsinki, Department of Physical Sciences, P.O. Box 64, FIN-00014 University of Helsinki, Finland
The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.