Configuration interaction studies of the HeH+ molecular ion. III. Singlet pi and delta states

Abstract

The method of superposition of configurations is applied to the singlet pi and delta states of HeH+ which correlate to the separated atom states of principal quantum number less than or equal to 3. The calculations are carried out for internuclear separations R in the range 0(0.1)34.5, 35.0(0.5)50.0 a.u. The delta state calculations are also extended to R=65. The work is a continuation of a study of HeH+ for which the singlet sigma states have already been reported. In addition to the energy eigenvalues, matrix elements for radial and angular coupling and the dipole and gradient matrix elements are calculated for all combinations of the singlet sigma, pi, and delta states. Plots and tables of the calculated eigenvalues and matrix elements are presented. Where possible the calculated data are compared with the results of previous work. The results of this work are useful for theoretical collision studies of H++He and H+He+.