Pressure Shifts of High-Series Spectral Lines and Cross Sections for Scattering of Very Slow Electrons from Rare-Gas Atoms
M. H. Choudhury
A completely quantum-mechanical theory of the pressure shift of high-series spectral lines of alkali atoms by foreign gases (usually inert gases) is presented. In this version of the theory, the Schr\"odinger equation for the whole system consisting of the excited alkali atom and the foreign gas is written, the interaction terms simplified, and the resulting equation solved by the methods of perturbation theory. The main qualitative results of Fermi's theory are reproduced, together with contributions from other terms which have no analog in Fermi's theory, and whose interpretation leads to interesting physical consequences justified by experimental observations. In particular, values of the total cross section for the scattering of very slow electrons at effective electron kinetic energies between 0.034 and 0.21 eV are obtained, and found to be in fair agreement with those obtained directly from experiment. For argon, krypton, and xenon, these results indicate the existence of the Ramsauer-Townsend effect.
Physical Review•Oct 5, 1969•13 citations