A restricted quantum reaction path Hamiltonian: theory, discrete variable representation propagation algorithm, and applications.

A derivation of a quantum reaction path Hamiltonian is proposed, which is based on a reformulation of the classical version of Gonzalez et al. [J. Phys. Chem. A 105, 5022 (2001)], and the resulting equations are solved by means of a discrete variable representation approach, leading to a well-suited algorithm for the calculation of quantum dynamics of chemical reactions involving polyatomic molecules. General expressions for any type of reaction path are presented with special interest in the intrinsic reaction coordinate, which have been used to study selected cases, including a one-dimensional Eckart barrier, for which results are shown to be exact, two bidimensional systems, namely, a Muller-Brown potential energy surface, which is characteristic of polyatomic isomerization processes, and the collinear H + H(2) chemical reaction, and finally the tridimensional, J = 0, F + H(2) reaction. Results for the specific chemical systems are shown to be in quite good agreement with exact two- and three-dimensional quantum calculations concerning autocorrelation functions as well as transmission factors as a function of total energy.