Electronic states of NH and OH+

Abstract

Ab initio calculations (LCAO-MO-SCF) nearing Hartree-Fock accuracy were made for a series of valence states of the molecules NH and OH+. The correlation energies of all states considered were calculated by a method used precedingly and described in this work. Good agreement with experimental data is found for a series of molecular properties such as equilibrium internuclear distances, term values, dissociation energies and ionization potentials; fair agreement is found for vibration frequencies and unharmonic constants. The precision of the present calculations allow definite predictions to be made concerning the relative energies of the singlet and triplet states in NH, and concerning the potential energy curves of unobserved singlets in OH+. Finally, the examination of the dissociation properties of the electronic states from calculations carried out at large internuclear distances, make it possible to reach conclusions concerning the eventual presence of potential maxima in their potential energy curves.