Program Version: 9.3/P9.3-M3.1
Program Version Date:January 3, 2004
Manual Version Date: July 21, 2021

Copyright 2001-2004

Abstract: MULTILEVELRATE is a set of FORTRAN 77 subroutines and Unix shell scripts for interfacing the POLYRATE and MULTILEVEL computer programs for the purpose of carrying out direct dynamics calculations of gas-phase chemical reaction rates of polyatomic species (and also atoms and diatoms as special cases) using the electronic structure methods available in MULTILEVEL to calculate the potential energy surface and POLYRATE for the dynamics. The interface is based on the POLYRATE hooks protocol. The dynamical methods used are variational or conventional transition state theory and multidimensional semiclassical approximations for tunneling and nonclassical reflection. Rate constants may be calculated by any of the methods available in the POLYRATE-version 9.3 program for canonical or microcanonical ensembles or for specific vibrational states of selected modes with the translational, rotational, and other vibrational modes treated thermally. Bimolecular and unimolecular reactions are included. Both single-level and dual-level dynamics calculations may be carried out. In single-level mode, optimized geometries, potential energies, gradients, and Hessians can be calculated by any of the integrated molecular orbital (imo) methods and linear combination (lc) methods provided by the multilevel package. In dual-level mode, the lower-level data is calculated by multilevel, and the higher-level data is read in from an external file.

The user needs to obtain the following packages:

From the University of Minnesota:

POLYRATE: POLYRATE is available from the University of Minnesota. For further information about POLYRATE see http://comp.chem.umn.edu/polyrate.

MULTILEVEL: MULTILEVEL is available from the University of Minnesota. For further information about the MULTILEVEL code see http://comp.chem.umn.edu/multilevel.