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Title: Simultaneous TOF spectra of sputtered and scattered neutrals and ions from 3 keV Ne/sup +/, Ar/sup +/, and Ar/sup 2 +/ bombardment of CsBr

Journal Article · · J. Chem. Phys.; (United States)
OSTI ID:6148892

A spectrometer system for simultaneous mass and velocity analysis of scattered and sputtered ions and velocity analysis of fast neutrals ejected from a surface by bombardment with a pulsed ion beam is described. Combination secondary ion and scattered neutral plus ion TOF spectra and their corresponding energy spectra for 3 keV Ar/sup +/ and Ar/sup 2 +/ bombardment of CsBr are presented. Selective sputtering of Br down to a steady state level is observed with Ne/sup +/ bombardment with an estimated depletion cross section of 10 A/sup 2/. Scattering spectra of neutrals plus ions and neutrals alone allow determination of scattered Ar/sup +/ ion survival fractions of 0.22 and 0.13 from 3 keV Ar/sup +/ collisions with Cs and Br, respectively. This indicates preferential neutralization during scattering from Br. Ion fractions for Ar/sup 2 +/ and Ar/sup +/ are determined for Ar/sup 2 +/ scattering, illustrating the stepwise neutralization process for multiply charged ions. With 3 keV Ar/sup 2 +/ bombardment the fractions surviving as Ar/sup +/ for Cs and Br collisions are 0.18 and 0.08, respectively, while the fraction surviving as Ar/sup 2 +/ is approx.0.10 for both atomic collisions. The ion fraction data are interpreted in terms of Auger and resonant neutralization transitions between the ion and specific surface atoms.

Research Organization:
Department of Chemistry, The University of Houston, Houston, Texas 77004
OSTI ID:
6148892
Journal Information:
J. Chem. Phys.; (United States), Vol. 78:8
Country of Publication:
United States
Language:
English