Accession Number : ADA329695

Title :   Reactions of Atmospheric Cluster Ions.

Descriptive Note : Final technical rept.,

Corporate Author : COLORADO UNIV AT BOULDER

Personal Author(s) : Leone, Stephen R. ; Bierbaum, Veronica M.

PDF Url : ADA329695

Report Date : 31 JUL 1997

Pagination or Media Count : 7

Abstract : A selected ion flow tube apparatus has been modified to include a well-defined flow drift region and instrumentation for ion modulation and data acquisition. This apparatus was used to measure the first experimental mobilities for several important families of atmospheric cluster ions. Core ions include the nitric oxide cation, ammonium ion, and hydronium ion; solvating ligands include water, ammonia, acetonitrile, and acetone. Several collision gases were examined including helium and nitrogen, as well as the polar gases, water and acetone. The mobilities of prototypical aromatic species have also been measured and evaluated to distinguish between isomeric structures. Doppler-resolved laser-induced fluorescence measurements of collision-induced rotational alignment of the molecular nitrogen cation drifted in helium have been carried out. A strong correlation was found between the degree of rotational alignment and the velocity subgroup probed along the field direction; the correlation between alignment and velocity increases with increasing field strength. These results are attributed primarily to the change in anisotropy of the relative velocity vector distribution of the nitrogen cation-helium pair with field strength. the nitrogen cation-helium pair with field strength.

Descriptors :   *ATMOSPHERIC CHEMISTRY, MOBILITY, LASER INDUCED FLUORESCENCE, ACETONITRILE, AMMONIA, CLUSTERING, DOPPLER SYSTEMS, NITROGEN OXIDES, ACETONES, PARTICLE COLLISIONS.

Subject Categories : Atmospheric Physics
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE