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ELECTRON COLLISION CROSS SECTION FOR HELIUM

Thesis/Dissertation ·
OSTI ID:4733965

The Exchange Distorted Born-Oppenheimer (EDBO) approximation and the method of partial cross sections were used to calculnte the effective elastic collision cross section as a function of the energy of slow electrons incident on normal helium (1/sup 1/S) and to calculate the effective inelastic collision cross section as a function of the incident electron energy for the 1/sup 1/S --2/ sup 3/S transition. The EDBO approximation allows for distortion of the scattered electron wave by both exchange and potential interaction with the helium atom. Only S-wave scattering (scattering of an incident electron with an angular momentum quantum number of 0) is considered in the elastic scattering calculation, while both S-wave scattering and P-wave scattering (scattering of an electron with an angular momertum quantum number of 1) are considered in the inelastic scattering calculation. An open shell wave function is used to represent the helium atom in the 1/sup 1/S state. The integro-differential equation, which determines the elastic scattering, is solved by Hulthen's variational method, using two different trial functions to represent the distorted electron wave. The trial functions were chosen to satisfy certain boundary conditions, and each contained three variational parameters (one of which specified the phase shift of the distorted electron wave). The results compare favorably with experimental values and are slightly superior to earlier calculations, which have used the same approximations but simpler wave functions to represent the 1iS state and the elastically scattered wave. (Dissertation Abstr., 23: No. 5, Nov. 1962)

Research Organization:
Originating Research Org. not identified
NSA Number:
NSA-17-009145
OSTI ID:
4733965
Country of Publication:
Country unknown/Code not available
Language:
English