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Anomalous behavior in differential cross sections for the 2 sup 3 S excitation in helium at minute scattering angles for fast electron collisions

Journal Article · · Physical Review, A; (USA)
; ; ; ; ;  [1]; ;  [2]
  1. Department of Physics, Sophia University, Chiyoda-ku, Tokyo 102, Japan (JP)
  2. Institute for Laser Science, University of Electro-Communications Chofu-shi, Tokyo 182 (Japan)

Differential cross sections (DCS) for the 1 {sup 1}{ital S}{minus}2 {sup 3}{ital S} excitation in helium have been measured with a high angular resolution of about 1{degree} as a function of the scattering angle {theta} from 12{degree} to 0{degree} for the incident energies of 200 and 500 eV. For the incident energy of 500 eV, the DCS increases drastically as the angle decreases in the angular range smaller than 4{degree} and reaches a value 0.075 {ital a}{sub 0}{sup 2}/sr at {theta}=0{degree}, the increase being nearly 3 orders of magnitude. The DCS at zero scattering angle for impact energies from 200 to 800 eV have been measured. The DCS's are found to be about 1 order of magnitude greater than those of published measurements by Skerbele, Harshbarger, and Lassettre (J. Chem. Phys. 58, 4285 (1973)) and Klump and Lassettre (J. Chem. Phys. 62, 1838 (1975)).

OSTI ID:
5715699
Journal Information:
Physical Review, A; (USA), Journal Name: Physical Review, A; (USA) Vol. 43:3; ISSN 1050-2947; ISSN PLRAA
Country of Publication:
United States
Language:
English