On the continuous absorption coefficient of the negative hydrogen ion. II

Abstract

In this paper the continuous absorption coefficient of the negative hydrogen ion, determined in an earlier paper (Ap. J., 102, 223, 1945) in terms of the matrix elements of the momentum operator, is further improved to take into account the effect of the static field of the hydrogen atom on the motion of the ejected electron. It is shown that for wave functions for the ground state of H^- of the forms generally considered, the formula for the absorption cross-section can be reduced to the form K=3.7062/k(k²+0.05512)|∫^∞₀W₂(r)χ₁(r)dr|×10^-18 cm²,where k denotes the momentum of the ejected electron in atomic units, W₂(r) a certain weight function which can be tabulated, and χ₁(r) the radial part of a p-spherical wave in the Hartree field of a hydrogen atom which tends to unit amplitude at infinity. The absorption cross-sections of H^- have been evaluated according to the foregoing formula for various wave lengths. It is found that the new values are larger than those obtained with a plane-wave representation of the outgoing electron by about 5 per cent in the visual and the near infrared regions. The new absorption-curve places the maximum at about λ8500 A; at this wave length the atomic absorption coefficient has the value 4.52×10^-17 cm².