Using simply contracted basis functions with the Lanczos algorithm to calculate vibrational spectra

摘要

We demonstrate that the combination of simply contracted basis functions and the Lanczos algorithm yields an extremely efficient method for computing vibrational energy levels. In this paper we discuss the ideas, and present some results for CH_4. The basis functions we use are products of eigenfunctions of reduced-dimension Hamiltonians obtained by freezing coordinates at equilibrium.