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K -shell ionization of O sup 4+ and C sup 2+ ions in fast collisions with H sub 2 and He gas targets

Journal Article · · Physical Review A. General Physics; (United States)
; ; ;  [1];  [2]; ;  [3]
  1. J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)
  2. Department of Physics, U.S. Naval Academy, Annapolis, Maryland 21402 (United States)
  3. Department of Physics, Tulane University, New Orleans, Louisiana 70118 (United States)

Cross sections for 1{ital s} ionization of the 1{ital s}{sup 2}2{ital s}{sup 2} and 1{ital s}{sup 2}2{ital s}2{ital p}{sup 3}{ital P} (metastable) states of C{sup 2+} and O{sup 4+} ions in 0.5--1.8 MeV/{ital u} collisions with H{sub 2} and He targets were measured using projectile Auger electron spectroscopy at 0{degree}. Calculations of the {ital K}-shell ionization cross section {sigma}{sub {ital K}} were performed including contributions from projectile-electron--target-nucleus interactions ({sigma}{sub {ital e}{ital n}{ital I}}) within a plane-wave Born approximation (PWBA), and contributions from projectile-electron--target-electron interactions ({sigma}{sub {ital e}{ital e}{ital I}}) within an impulse approximation (IA). The theoretical total cross section {sigma}{sub {ital K}}={sigma}{sub {ital e}{ital n}{ital I}}+{sigma}{sub {ital e}{ital e}{ital I}} was found to be in overall agreement with the {ital K}-shell ionization measurements indicating a contribution of up to {similar to}30% due to electron-electron interactions. Separate screening-antiscreening calculations of {sigma}{sub {ital K}} were also performed and found to be in overall agreement with our data. Additionally, our PWBA-IA ionization calculation was also tested for H-like projectiles and found to be in agreement with recently published data. These results suggest that the IA calculation of {sigma}{sub {ital e}{ital e}{ital I}} when combined with a PWBA calculation of {sigma}{sub {ital e}{ital n}{ital I}} is quite adequate for describing {ital K}-shell ionization.

OSTI ID:
7034839
Journal Information:
Physical Review A. General Physics; (United States), Journal Name: Physical Review A. General Physics; (United States) Vol. 46:3; ISSN 1050-2947; ISSN PLRAA
Country of Publication:
United States
Language:
English