Variational Calculation of the Elastic

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. One of the important problems of upper atmospheric and astrophysical research is the determination of the frequencies of collisions between electrons and atomic systems. Informa tion on this subject can be obtained from a knowledge of the total cross-section, Q, and to some extent from the differential cross-section, (hg), of the collision. The temperatures at which these collisions occur are of such a magnitude that the electron energies are of the order of a fraction of an electron volt, and at these low energies the problems associated with experimental determinations of the cross-sections become complex. Consequently there is a deficiency of experimental data. It is therefore essential to have theoretical methods for calculating the cross-sections.