Hartree—Fock—Roothaan Wavefunctions, Potential Curves, and Charge-Density Contours for the HeH+(X 1Σ+) and NeH+(X 1Σ+) Molecule Ions

Abstract

Hartree—Fock—Roothaan wavefunctions for the ground state of the HeH⁺ ion and the NeH⁺ ion are reported. The potential curves for HeH⁺ and NeH⁺ are calculated using wavefunctions, which are optimized at the equilibrium distance and also at each internuclear distance, and their relative behavior is discussed. The Hellmann—Feynman forces on the nuclei are studied as a function of the internuclear distance with regard to the size of the basis set and optimization of the wavefunction. Spectroscopic data are calculated in different ways, a dissociation energy of 1.74 eV for HeH⁺ and 2.03 eV for NeH⁺ is computed, and calculations made to find the center of negative charge for every internuclear separation. Electron‐density maps are plotted for several internuclear distances in HeH⁺ and for the total wavefunction and the individual molecular orbitals of NeH⁺ at the equilibrium distance.