A critical analysis of the ground and excited electronic states of transition metal nitrides using the relativistic effective Hamiltonian method

Abstract

Multireference many-body perturbative schemes (IVO-CASCI and Hv3rd), which are applicable to the direct calculation of excitation energies, ionization potentials, and spectroscopic properties, are presented and applied to compute the transition energies, ionization potentials, and spectroscopic constants of TiN and VN. Highly satisfactory results are obtained for the excitation energies, triple bond dissociation energy, dipole moments, oscillator strengths, and vibrational frequencies. The ground and excited properties of interest are also computed using Hartree-Fock and two-component Dirac-Hartree-Fock molecular orbitals to assess the importance of relativistic effects. We also report the ionization potentials of TiN+ and VN+ which are by-products of this method with ``no extra'' computational cost and which have not been studied previously