THE APPLICATION OF SPIN-COUPLED THEORY TO THE FIRST 5 (4)SIGMA(+) STATES OF HEH - A GENERALIZED SLIDE-RULE APPROACH

The potential energy curves for the five lowest (4) Sigma(+) states of HeH are computed using single-configuration spin-coupled wavefunctions. The three occupied orbitals are expanded in slide-rule form, using a basis set of He(12s,6p) and H(11s,5p) uncontracted Cartesian GTO orbitals, and the energy obtained for each separately optimized quartet state is close to published MRD-CI values. The convergence characteristics of the energy minimization procedure are facilitated through the use of the invariance properties of the single-determinant wavefunction under transformations on the set of occupied orbitals.