Theoretical studies of certain atomic collisions. I. Electron loss from H- in H and ionization of lithium by fast protons and electrons. II. Transport properties of an ionized gas

Abstract

General formulations of the quantal theory of collisions between two atomic systems are available and the relevant sections are summarized in Chapter I. The results of Born can then be applied in Chapter II to the problem of electron loss from fast H passing through its parent gas at impact energies lying between 2.5 kev and 10 Mev. The sensitivity of the cross sections for which either of the resultant H atoms is excited to the 2p state, to the choice of bound and free wave functions is examined and the total loss cross section is compared with data on electron loss in H2 and H. The same theory is used in Chapter III to study the excitation and ionization of Lithium by fast electron and proton impact at incident energies up to 1 kev and 1 Mev respectively. The ionization cross sections obtained using Seaton's method (1959) yield comparison material, and the excitation calculation so far tested for sensitivity to choice of orbital parameters. In Chapter IV the rather different methods used for treating slow collisions between electrons and positive ions are employed to gain information on the diffusion and viscosity cross sections and hence on the transport coefficients, in particular the electrical and thermal conductivities. Various numerical and analytical approximations are obtained for these quantities, in the ranges 10 °K - 10 K and 10 -101 per cm3 of temperature and electron number density respectively It is shown that the electrical conductivity passes through a maximum at a temperature which is possibly in the laboratory range for high number densities. The numerical results are summarized in a series of tables.