Selected Topics from the Theory of Electron-Atom and Atom-Atom Collisions.
Abstract
The quantal elastic, diffusion and viscosity cross-sections have been calculated for proton-helium, neon, argon, krypton, potassium ion-helium, neon and lithium ion-helium systems by means of standard phase shift sums over angular momentum. The classical diffusion and viscosity cross-sections for the above ion-rare gas systems and for the potassium ion-argon, lithium ion-neon, argon and sodium ion-helium, neon, argon were also calculated. At low relative momenta, the classical cross-sections serve only as a 'mean' about which the quantal cross sections oscillate, but the agreement improves with increasing relative momenta. The Vainshtein, Presnyakov and Sobel'man approximation was shown to be applicable to the excitation of metastable helium by electron impact. The cross-section up to 500 eV for electron-metastable helium collisions were calculated. Contrary to expectation, excitation to the optically-forbidden levels dominate that to the optically-allowed levels at energies below 100eV. The use of the Massey-Mohr approximation in the theory of atomic collisions is discussed. It is shown to have rather general application. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1978
- Accession Number
- ADA062610
Entities
People
- M. R. Flannery
- Walter Fredrick Morrison
Organizations
- Georgia Tech