AB INITIO APPROACH TO VIBRATIONAL PROPERTIES AND QUANTUM DYNAMICS OF MOLECULES

Although recent advances in quantum-chemical theory and computer technology have greatly facilitated the ab initio calculations of vibrational properties of molecules, systematic discrepancies between the calculated normal-mode frequencies and the observed fundamental frequencies persist and are especially notable in the high-frequency regime because of the nuclear quantum effects which are usually neglected in the calculations. In this paper, a new ab initio computational scheme to treat the molecular quantum dynamics is proposed on the basis of the variational quantum Monte Carlo method to describe the electronic structure combined with the centroid molecular dynamics method for the quantum nuclei in the framework of a fictitious Lagrangian dynamics.