Auto-ionization states of two electron atoms

Abstract

Auto-ionization energies of He and H- converging on the n=3 and n=4 hydrogenic thresholds are computed for states of several different symmetries by using the Feshbach formalism. Eigenvalues of the appropriate QHQ operator are determined by the Rayleigh-Ritz variational method. The trial wavefunction consists of an expansion in terms of the products of hydrogenic states and the exponentially decaying functions. Comparison is made with the experimental results and with other theoretical studies.