THEORETICAL-STUDY OF THE ELECTRONIC-SPECTRUM OF THE COH MOLECULE

Calculated potential energy curves and spectroscopic parameters of the ground and various low-lying excited states of the cobalt hydride molecule are presented, Over 30 electronic states of singlet, triplet, and quintet multiplicity have been obtained with adiabatic excitation energies below 4 eV. In addition, the electronic structure of several negative ion states has been determined. CoH- possesses a 4PHI electronic ground state and at least three other electronic states that are stable with respect to electron autodetachment. The calculations include relativistic effects variationally by employing a one-component no-pair operator with external-field projectors. Electron correlation is accounted for by using multireference single and double excitation configuration interaction methods. Several experimentally observed bands in the optical spectrum of CoH are ascribed to transitions between the X3PHI ground state and excited states of 3PHI, 3DELTA, and 1GAMMA symmetry.