Polyrate 2023: A computer program for the calculation of chemical reaction rates for polyatomics. New version announcement

Polyrate 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 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 reactions at gas–solid interfaces. Polyrate can perform 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. The RP methods used for tight transition states are conventional transition state theory, canonical variational transition state theory (CVT), and microcanonical variational transition state theory (μVT) with multidimensional semiclassical approximations for tunneling and nonclassical reflection. For VRC calculations, rate constants may be calculated for canonical or microcanonical ensembles or energy and total angular momentum resolved microcanonical ensembles. Pressure dependent rate constants for elementary reactions can be computed using system-specific quantum RRK theory (SS-QRRK) with the information obtained from high pressure limit VTST calculation as input by using the SS-QRRK utility code. Alternatively, Polyrate 2023 may be interfaced with TUMME 2023 for a master equation treatment of pressure dependence or to obtain phenomenological rate constants for complex mechanisms. Potential energy surfaces may be analytic functions evaluated by subroutines, or they may be implicit surfaces defined by electronic structure input files or interface subroutines containing energies, gradients, and force constants (Hessians). For the latter, Polyrate can be used in conjunction with various interfaces to electronic structure programs for direct dynamics, and it has routines designed to make such interfacing straightforward. Polyrate supports six options for direct dynamics, namely (i) straight single-level direct dynamics, (ii) zero-order interpolated variational transition state theory (IVTST-0), (iii) first-order interpolated variational transition state theory (IVTST-1), (iv) interpolated variational transition state theory by mapping (IVTST-M), (v) variational transition state theory with interpolated single-point energies (VTST-ISPE), and (vi) variational transition state theory with interpolated optimized corrections (VTST-IOC). Polyrate can handle multistructural and torsional-potential anharmonicity in conjunction with the MSTor program.Polyrate是一套用于通过变分过渡态理论（variational transition state theory，VTST）计算多原子物种（包括作为特殊情况的原子和双原子分子）化学反应速率的计算机程序套件，同时也支持传统过渡态理论。Polyrate可计算双分子反应与单分子反应的速率常数，可应用于气相、液态溶液相或固态中的反应，以及气-固界面处的反应。Polyrate可针对具有紧过渡态和松过渡态的气相反应开展变分过渡态理论计算。针对紧过渡态，其采用Garrett与Truhlar提出的反应路径（reaction path，RP）变分过渡态理论；针对松过渡态，则采用Georgievskii与Klippenstein提出的可变反应坐标（variable reaction coordinate，VRC）变分过渡态理论。用于紧过渡态的RP方法包括传统过渡态理论、正则变分过渡态理论（canonical variational transition state theory，CVT），以及带有隧穿和非经典反射多维半经典近似的微正则变分过渡态理论（microcanonical variational transition state theory，μVT）。对于可变反应坐标计算，可针对正则系综或微正则系综，亦或是能量与总角动量分辨的微正则系综计算速率常数。基元反应的压力相关速率常数可通过系统专属量子RRK理论（system-specific quantum RRK theory，SS-QRRK）进行计算，该方法以高压极限下变分过渡态理论计算得到的结果作为输入，需借助SS-QRRK实用程序代码实现。此外，Polyrate 2023可与TUMME 2023对接，用于压力依赖性的主方程处理，或为复杂反应机理获取唯象速率常数。势能面既可以是由子程序计算的解析函数，也可以是由电子结构输入文件或包含能量、梯度与力常数（海森矩阵）的接口子程序定义的隐式势能面。针对后者，Polyrate可与各类电子结构程序接口配合用于直接动力学计算，且内置了简化此类对接流程的程序模块。Polyrate为直接动力学计算提供六种选项，分别为：(i) 单层直接动力学，(ii) 零阶插值变分过渡态理论（IVTST-0），(iii) 一阶插值变分过渡态理论（IVTST-1），(iv) 基于映射的插值变分过渡态理论（IVTST-M），(v) 带有插值单点能校正的变分过渡态理论（VTST-ISPE），以及(vi) 带有插值优化校正的变分过渡态理论（VTST-IOC）。Polyrate可结合MStor程序处理多结构与扭转势非谐性。