Dietschreit Johannes C B, Diestler Dennis J, Gómez-Bombarelli Rafael
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
University of Nebraska-Lincoln, Lincoln, Nebraska 68583, United States.
J Chem Theory Comput. 2023 Aug 22;19(16):5369-5379. doi: 10.1021/acs.jctc.3c00448. Epub 2023 Aug 3.
The description of chemical processes at the molecular level is often facilitated by the use of reaction coordinates or collective variables (CVs). The CV measures the progress of the reaction and allows the construction of profiles that track how specific properties evolve as the reaction progresses. Whereas CVs are routinely used, especially alongside enhanced sampling techniques, the links among reaction profiles, thermodynamic state functions, and reaction rate constants are not rigorously exploited. Here, we report a unified treatment of such reaction profiles. Tractable expressions are derived for the free-energy, internal-energy, and entropy profiles as functions of only the CV. We demonstrate the ability of this treatment to extract quantitative insight from the entropy and internal-energy profiles of various real-world physicochemical processes, including intramolecular organic reactions, ionic transport in superionic electrolytes, and molecular transport in nanoporous materials.
在分子水平上描述化学过程通常借助反应坐标或集体变量（CVs）来实现。集体变量衡量反应的进程，并能构建出反映特定性质随反应进展如何演变的曲线。虽然集体变量被常规使用，尤其是与增强采样技术一起使用时，但反应曲线、热力学状态函数和反应速率常数之间的联系并未得到充分利用。在此，我们报告了对这类反应曲线的统一处理方法。我们推导出了仅作为集体变量函数的自由能、内能和熵曲线的易处理表达式。我们展示了这种处理方法从各种实际物理化学过程的熵和内能曲线中提取定量见解的能力，这些过程包括分子内有机反应、超离子电解质中的离子传输以及纳米多孔材料中的分子传输。
