Calcuiation of vibrational frequencies through a variational reduced-coupling approach

摘要

In this study,we present a new method to perform accurate and efficient vibrational configuration interaction computations for large molecular systems.We use the vibrational self-consistent field (VSCF) method to compute an initial description of the vibrational wave function of the system,combined with the single-to-all approach to compute a sparse potential energy surface at the chosen ah initio level of theory.A Davidson scheme is then used to diagonalize the Hamiltonian matrix built on the VSCF virtual basis.Our method is applied to the computation of the OH-stretch frequency of formic acid and benzoic acid to demonstrate the efficiency and accuracy of this new technique.