A discrete variable representation method for studying the rovibrational quantum dynamics of molecules with more than three atoms

Established multidimensional discrete variable representations (DVRs) are derived from a direct product basis. They are commonly used to compute vibrational spectra and have also been employed to determine rovibrational spectra of triatomic molecules. We show that for J>0 calculations the DVR is also advantageous for molecules with more than three atoms. We use a basis of products of Wigner functions (for rotation) and DVR functions (for vibration). A key advantage of the DVR is the fact that one can prune the basis: many DVR functions can be discarded from the original direct product basis. This significantly reduces the cost of the calculation. We have implemented a mapping procedure to exploit this prune-ability. We explain how to treat Coriolis terms in a parity-adapted basis. The method is tested by computing rovibrational levels of HFCO.