A study with a complete-active-space self-consistent-field plus density functional theory combination: The low-lying bound states of N 2

Abstract

The use of a large set of correlation energy functionals, in a post-self-consistent-field procedure, is analyzed for the calculation of the potential-energy curves of the ground state and some excited states in the case of the N2 molecule. The results show the improvement of the molecular properties, such as dissociation energies, equilibrium bond distances and harmonic vibrational frequencies, (when some of the tested functionals are used), together with the problems that the use of density functional theory functionals applied to multideterminantal wave functions implies.