Anomalous behavior in differential cross sections for the 2 sup 3 S excitation in helium at minute scattering angles for fast electron collisions
- Department of Physics, Sophia University, Chiyoda-ku, Tokyo 102, Japan (JP)
- 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
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Related Subjects
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR CORRELATION
ATOM COLLISIONS
COLLISIONS
CORRELATIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELECTRON COLLISIONS
ELECTRON-ATOM COLLISIONS
ELEMENTS
ENERGY DEPENDENCE
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EV RANGE
EV RANGE 100-1000
EXCITATION
EXCITED STATES
FLUIDS
GASES
HELIUM
METASTABLE STATES
NONMETALS
RARE GASES