• TUMME: Tsinghua University Minnesota Master Equation program

    • A program for assembling and solving master equations for gas-phase chemical kinetics
    • Based on chemically significant eigenmodes
    • Calculates microcanonical flux coefficients (input to master equation) by multi-structural variational transition state theory with small-curvature tunneling (MS-VTST/SCT) or by conventional transition state theory by using data read from output files of Gaussian, Polyrate, and/or MSTor
    • Written in double precision with Python 3
    • Quadruple and octuple precision are also available for some subtasks in C++
    • Python code can run in serial or parallel (MP or MPI), and C++ code can run on a single processor or on multiple processors with openMP
    • For more details: https://comp.chem.umn.edu/tumme/

  • MSTor: A program for calculating partition functions, free energies, enthalpies, entropies, and heat capacities of complex molecules including torsional anharmonicity

    MSTor is a computer program for calculating gas-phase molecular partition functions and thermodynamic functions (standard state energy, enthalpy, entropy, free energy, and heat capacity at constant pressure) as functions of temperature by the multi-structural approximation with torsional anharmonicity (MS-T). The MS-T method is especially designed for the convenient treatment of molecules with many conformational structures generated by internal rotations (torsions). The default method in MSTor is the multi-structural approximation with torsional anharmonicity, a coupled torsional potential, and delocalized torsions, abbreviated as MS-T(CD), but the program also supports the older MS-T(U) and MS-T(C) methods, the multi-structural local harmonic (MS-LH) approximation, and the multi- structural local quasiharmonic (MS-LQ) approximation. The MS-T methods account for the coupling of torsions to one another and to overall rotation and, to some extent, the coupling between torsions and other vibrational modes. By combining a redundant-internal-coordinate auto-generation procedure with torsional projection techniques, MSTor automates the identification of torsional vibrations and their separation from the other vibrational modes; this reduces the needed user input.

    MSTor includes eight utility codes that can be used as stand-alone programs. One utility program calculates reduced moments of inertia by the method of Kilpatrick and Pitzer, one generates conformational structures, the third and fourth calculate volumes of torsional subdomains defined by Voronoi tessellation either analytically or by Monte Carlo sampling, the fifth and the sixth generates template input files, and the seventh calculates one-dimensional torsional partition functions using the torsional eigenvalue summation method. The final utility code is for computing dual level MS-T partition functions.

  • Polyrate: A Computer Program for the Calculation of Chemical Reaction Rates for Polyatomics.

    Polyrate 2023 is a suite of computer programs for the calculation of chemical reaction rates of polyatomic species (including atoms and diatoms as special cases) by variational transition state theory (VTST); conventional transition state theory is also supported. Polyrate 2023 (called Polyrate for short) consists of the main program, called POLYRATE, and a set of utility codes.

    Polyrate can calculate the rate constants for both bimolecular reactions and unimolecular reactions, and it can be applied to reactions in the gas‑phase, liquid-solution phase, or solid-state and to gas‑solid‑interface reactions. Polyrate can perform variational transition state theory (VTST) calculations on gas-phase reactions with both tight and loose transition states. For tight transition states it uses the reaction-path (RP) variational transition state theory developed by Garrett and Truhlar, and for loose transition states it uses variable-reaction-coordinate (VRC) variational transition state theory developed by Georgievskii and Klippenstein.