Collision-induced ion-pair formation of CsCl and Cs/sub 2/Cl/sub 2/

Journal Article · Thu Jun 01 00:00:00 EDT 1978 · J. Chem. Phys.; (United States)

OSTI ID:6842833

Sheen, S H; Dimoplon, G; Parks, E K; Wexler, S

Absolute cross sections have been determined for collision-induced ion-pair formation of cesium chloride (monomers and dimers) from collisions with Ar, Kr, and Xe atoms. The rare gas atoms were aerodynamically accelerated in H/sub 2/, with maximum energies of 6.8, 12.1, and 18.3 eV (in the laboratory frame), respectively. Time-of-flight mass spectrometry permitted the determination of partial cross sections for each ion channel resulting from the collision. For the monomer, the cross secions for the channel leading to Cs/sup +/+Cl/sup -/ were similar in magnitude for the three rare gas atoms and were approximately 3 x 10/sup -/16 cm/sup 2/ at 3 eV above threshold. The rearrangement ionization channel leading to CsM/sup +/ (M=Ar, Kr, and Xe) exhibited a step behavior at threshold followed by a very rapid fall off at higher collision energies. Collisions with the dimers produced both Cs/sub 2/Cl/sup +/+Cl/sup -/ and Cs/sup +/+CsCl/sup -//sub 2/ but no detectable ions containing the rare gas atoms. The magnitude of the cross sections for the Cs/sub 2/Cl/sup +/ channel varied significantly with the rare gas although the corresponding thresholds were similar. In the case of CsCl/sup -//sub 2/, however, the magnitudes of the cross sections were similar, but the thresholds varied. A possible explanation for this difference in behavior is given based on simple dynamical models. The cross sections for each product ion from both the monomer and dimer (except for CsM/sup +/) exhibited a power-law rise with increasing energy sigma=const x (E/sub tot/-E/sub 0/)/sup n//E/sub rel/ up to about 1--1.15 eV above threshold, where E/sub tot/ is the total energy, E/sub 0/ the threshold energy, and E/sub rel/ the relative kinetic energy. Values of n and E/sub 0/ were determined for each system. The threshold for each reaction M+CsCl..-->..M+Cs/sup +/+Cl/sup -/ was determined most accurately from the peak in the CsM/sup +/+Cl/sup -/ excitation function, which occurs (after energy deconvolution) at the threshold for collision-induced dissociation.

• Research Organization: Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
• OSTI ID: 6842833
• Journal Information: J. Chem. Phys.; (United States), Vol. 68:11
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ATOM-MOLECULE COLLISIONS
CESIUM CHLORIDES
KRYPTON
XENON
CROSS SECTIONS
ION PAIRS
IONIZATION
MASS SPECTROSCOPY
ALKALI METAL COMPOUNDS
ATOM COLLISIONS
CESIUM COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
COLLISIONS
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
MOLECULE COLLISIONS
NONMETALS
RARE GASES
SPECTROSCOPY
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena