Accurate quantum molecular dynamics for multidimensional systems by the basis expansion leaping multi-configuration Gaussian (BEL MCG) method.

Abstract

Quantum phenomena are quite often of critical importance in chemical reactions. Thus the development of quantum molecular dynamics approaches is required to study the role of quantum effects such as tunnelling in chemical processes. The basis expansion leaping multi-configuration Gaussian (BEL MCG) method has been developed to obtain time-propagated wave packets describing reactive molecular systems. Here we examine the applicability of BEL MCG to double well problems in several dimensions. We pay particular attention to what is required to yield highly accurate dynamics with respect to several key features of the BEL MCG propagation. The importance of using basis functions of a width appropriate to the nature of the potential energy surface in the region of configuration space where each basis function is located is highlighted, which has implications for virtually all quantum molecular dynamics methods utilising Gaussian basis functions.