Continuous absorption by carbon negative ions and other quantal calculations

Abstract

The purpose of this work is to provide reasonably accurate data on continuous absorption by Carbon negative ions for astrophysical applications. Chapter 1 contains a brief discussion on atomic negative ions, and the theoretical formulation of the photo detachment process hv + c- -> e + c. A short account of the available data on photo detachment is given, and the need for more comprehensive theoretical results for ions other than H is indicated. In Chapter 2 various separable orbital approximations to the photo detachment cross section of C are considered; Hartree Fock wave functions for the bound electrons and static central field exchange functions for the continuum electron being those finally adopted. The effects of continuum correlation are also discussed. Chapter 3 gives a short account of elastic scattering of slow electrons by atoms, and results for the process e + c -> e + c are presented in the static central field exchange approximation. In Chapter 4 the free transitions hv + e + c -> e + c of an electron in the field of a carbon atom are discussed, and the final results for the continuous absorption coefficient of C are presented over a wide range of temperatures and wavelengths. Chapter 5 gives a brief survey of the problem of model stellar atmospheres, and indicates how the results of the earlier chapters may be used to compute the theoretical spectrum of model stars with high carbon content.