A note on the status of recent enhancements to Polyrate

Major enhancements in version 2017-C:

• In the SS-QRRK utility code, a new approximation for treating unimolecular isomerization reaction has been added; the FE factor now can be evaluated via numerical integration instead of using the approximated analytical formula.

Major enhancements for version 2016-2A:

• A utility code for computing pressure-dependent rate constants by using SS-QRRK theory is added, which is able to include the variational effects, multi-dimensional tunneling, and various vibrational and torsional anharmonicity into the computed pressure-dependent rate constants and the SS-QRRK microcanonical rate constants.

Major enhancements for version 2016:

• The torsional anharmonicity can be computed along the reaction coordinate based on the single-structure MS-T(C) (MS-T method with coupled torsional potentials) formalism.
• The number of states calculation that is required for μVT is now programmed much more efficiently by the extended Beyer-Schwinehart method. Now there is no significant difference between CVT and μVT as far as computational cost.

Major enhancements for version 2010:

• One new keyword "FREQINCR" is added to raise low frequencies to a certain number (e.g., 50 or 100 cm^-1) to approximately account for anharmonicity.
• In rate calculations for barrierless association reactions by VRC-VTST, the reverse reaction (dissociation) rate is also calculated by the equilibrium constant and the association rate.
• The SPRNG 2.0 package is included in the Polyrate distribution.
• In VRC-VTST calculations, in calculating the total number of available states, the integrat ion over the projection on the principal axis (K) of the total angular momentum J is calculated analytically.
• Several methods for treating torsions, in particular the RPG, AS, SRPG, and SAS methods, are implemented.

A summary of major enhancements from versions 7.2 to 2008:

• Variable reaction coordinate variational transition state theory with multifaceted dividing surfaces for barrierless association reactions was implemented, and the code was parallized using MPI: 2008
• Default unit changed from Bohr to Angstrom in the input (fu5) and output (fu6) files: 9.7
• Compatibility with the gnu fortran compiler: 9.4
• Interpolated LCG algorithm (ILCG): 8.9
• Version 4 of large-curvature tunneling approximation (LCT4): 8.5
• Non-equilibrium solvation calculations: 8.2
• IVTST-M through the hooks: 8.0
• Variational reaction path (VRP) algorithm: 8.0
• Variational transition state theory with interpolated single point energies (VTST-ISPE): 8.0
• Interpolated variational transition state theory by mapping (IVTST-M), an IVTST method which allows arbitrary numbers of points along the reaction path, arbitrary numbers of points at which Hessians are computed, and leads to faster convergence of direct dynamics calculations: 7.8
• RODS algorithm for Re-Orienting the Dividing Surface to allow VTST calculations with larger step sizes: 7.8
• Redundant internal coordinates: 7.4
• Ability to optimize the reactants, the products, and the saddle point in separate runs: 7.4
• Curvilinear coordinates available for all standard types (stretches, nondegenerate bends, torsions, and degenerate bends): 7.2
• ICL and Eckart options for VTST-IC method: 7.2