Continuum-distorted-wave calculations for electron capture from hydrogen negative ions by fast protons

Abstract

The continuum-distorted-wave approximation has been used to determine the electron-capture cross sections sigma (nl,n'l') when fast protons impinge on the H^- target system. The range of the projectile energy extends up to 2 MeV and the quantum labels (nl) and (n'l') denote the electronic states of the captured and passive electrons, respectively. The authors have considered the states n (and n')=1 and 2 with l=0, 1 and l'=0. From these results, values of the total capture cross section Sigma have been determined using the Oppenheimer n^-3 rule. The target system is described, in turn, by a simple variational wavefunction, a Hartree-Fock function, a split-shell description, and finally, a configuration-interaction wavefunction which allows for over 99% of the electron correlation energy.