Molecular calculations for HeH+ with two-center correlated orbitals

Abstract

A two-center correlated orbital approach was used to calculate the electronic ground state energy for the HeH + molecular ion. The wavefunctions were constructed from the exact solution of the Schrödinger equation for the HeH ++ problem in prolate-spheroidal coordinates taken together with a Hylleraas type correlation factor. With a simple single term wavefunction, we obtained ground state energy of −2.95308691 hartree without any variational parameters in the calculation. When a two-configuration-state wavefunction was used and effective charges were allowed to be adjusted, we found an energy of −2.97384868 hartree, which is to be compared with −2.97869074 hartree obtained by an 83 term configuration interaction wavefunction or −2.97364338 hartree by an ab initio calculation (at the MP4(SDQ)/6-311++G(3df, 3dp) level) using the well-known "canned" code.HeH + , two-center orbitals, prolate-spheroidal coordinates, correlation function

A Quasi-Analytical Study of the Nonrelativistic Two-Center Coulomb Problem

“…Lau and Price to solve the three-dimensional helically reduced wave equation of two-center nature appearing in astrophysics [22] introduced a multidomain spectral-tau methodology. YuSheng et al studied two-center correlated orbital approach and reported the electronic ground state energy for the HeH + [23].…”