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Stochastic path‐integral method for chemical reaction dynamics: Application to the full 3D H 3 system
Author(s) -
Nagaoka Masataka
Publication year - 1996
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1996)60:7<1303::aid-qua11>3.0.co;2-5
Subject(s) - stochastic matrix , curse of dimensionality , path integral formulation , autocorrelation , statistical physics , amplitude , matrix (chemical analysis) , boltzmann constant , range (aeronautics) , chemistry , quantum , physics , quantum mechanics , mathematics , statistics , materials science , chromatography , markov chain , composite material
A stochastic path‐integral (SPI) technique for chemical reaction dynamics is explored. It is shown that this technique enables the direct computation of the transition amplitude with a finite space‐time range, by generating a set of classical paths subject to simultaneous stochastic differential equations. The numerical values of the Boltzmann matrix elements for a harmonic potential are in good agreement with the analytical ones. Within the quantum transition state theory, the flux‐flux autocorrelation function is also evaluated at 630 K for the H + H 2 exchange reaction and is found to give a satisfactory agreement with the previous studies. To appraise the influence of the dimensionality, both one‐dimensional Eckart potential and a full three‐dimensional (3D) Liu‐Siegbahn‐Truhlar‐Horowitz (LSTH) potential calculations have been performed. The calculated values of the Boltzmann matrix elements for the colinear and the full 3D cases are found to deviate slightly from each other in the lower temperature range. The 3D thermal rate constant is in very good agreement with the previous one. © 1996 John Wiley & Sons, Inc.