601. POLYRATE: A Computer Program for the Calculation of Chemical
Reaction Rates for Polyatomics (version 7.3.1)
POLYRATE is a computer program for the calculation of chemical reaction
rates of polyatomic species (and also atoms and diatoms as special cases).1,2
POLYRATE v. 7.3.1 is an enhanced version of POLYRATE with improved capabilities
for direct dynamics3 and curvilinear coordinates.4
The methods used are variational or conventional transition state theory5,6
and multidimensional semiclassical approximations for tunneling and nonclassical
reflection. Generalized transition state theory calculations may
be carried out using either rectilinear or non-redundant curvilinear coordinates.
Zero-curvature,7 centrifugal-dominant small-curvature,1,8,9
and large-curvature-version 3 (LC3)1,8 tunneling methods are
included, including tunneling into excited states in the LC3 model, and
optimized multidimensional tunneling10 is also included.
Rate constants may be calculated for canonical or microcanonical ensembles or for specific vibrational states of selected modes with translational, rotational, and other vibrational modes treated thermally. Bimolecular and unimolecular reactions and gas-phase, solid-state, and gas-solid-interface11 reactions are all included.
Potential energy surfaces may be analytic functions evaluated by subroutines, or they may be implicit surfaces defined by electronic structure input files containing energies, gradients, and force constants (Hessians) at selected points on a reaction path. The use of electronic structure calculations to calculate rate constants or other dynamical quantities without an analytic potential energy surface is called direct dynamics. In POLYRATE 7.3.1, analytic surfaces may be used for variational transition state theory and any of the types of tunneling calculations, single-level and dual-level calculations based solely on electronic structure input files may be used for variational transition state theory and zero-curvature or small-curvature tunneling, and dual-level calculations based on using an analytic potential energy surface as the lower level and using an electronic structure input file as the higher level may be used for variational transition state theory and any of the types of tunneling calculations.
Version 7.3.1 of POLYRATE supports four options for direct dynamics, namely (i) straight single-level direct dynamics, (ii) zero-order interpolated variational transition state theory (IVTST-0),12 (iii) first-order interpolated variational transition state theory (IVTST-1),12 and (iv) variational transition state theory with interpolated corrections (VTST-IC). VTST-IC is also called dual-level direct dynamics or triple-slash dynamics (///).13,14 Dual-level direct dynamics may be applied with electronic structure data for both levels, or it may be applied with an analytical potential energy surface for the lower level and electronic structure data for the higher level.
The program is completely described in a manual which is distributed as part of the program package in both PDF and PostScript formats. Further information, announcements of new versions, and related codes may be found at the URL: http://t1.chem.umn.edu/sds/
POLYRATE 7.3.1 requires a license. QCPE can provide copies of the non-profit license to persons who wish to order the program. The license should be signed and returned to QCPE with the program order. There is no additional fee above the usual QCPE service charges.
Lines of Code: 150,979 (includes FORTRAN source, PDF and compressed PostScript versions of the manual, input and partial output for 73 test runs, and C shell script for making Unix command files).
ANSI-standard FORTRAN77 (except that subroutine names are lower case)
with the INCLUDE and DO WHILE extensions. Tested successfully on
Cray C90 (UNICOS 8.03), IBM RS/6000 models 550 and 590 (AIX 4.1),
and Silicon Graphics Indigo-2 R10000 (IRIX 6.2).