Anharmonic Correction to Adsorption Free Energy from DFT-Based MD Using Thermodynamic Integration
Anharmonic Correction to Adsorption Free Energy from DFT-Based MD Using Thermodynamic Integration
复制标题
DOI：
10.1021/acs.jctc.0c01022
复制
发表时间：
2021-01-22
影响因子：
5.5
通讯作者：
Bucko, Tomas
中科院分区：
文献类型：
--
作者：
Amsler, Jonas;Plessow, Philipp N.;Bucko, Tomas
吸附过程通常由弱相互作用控制，对于弱相互作用，通过谐波近似估计熵贡献容易不准确。从谐波到完全相互作用系统的热力学积分（TI）（路径积分）可用于计算非谐波修正。在这里，我们结合联合收割机TI与（曲线）内坐标周期性系统，使计算研究中可用的形式。我们的从头算分子动力学在VASP中的实现是独立的反应路径，因此可以应用于研究相对于气相的吸附过程，并因此为计算催化提供了一个有用的工具。我们讨论了三个模型系统的方法的应用，精确的半解析解存在，并说明和量化的重要性，非谐振动，受阻旋转，受阻翻译（解离）。最后，我们应用该方法研究了小分子吸附物在分子筛（H-SSZ-13）上的吸附。
Adsorption processes are often governed by weak interactions for which the estimation of entropy contributions by means of the harmonic approximation is prone to be inaccurate. Thermodynamic integration (TI) from the harmonic to the fully interacting system (lambda-path integration) can be used to compute anharmonic corrections. Here, we combine TI with (curvilinear) internal coordinates in periodic systems to make the formalism available in computational studies. Our implementation of ab initio molecular dynamics in VASP is independent of the reaction path and can be thus applied to study adsorption processes relative to the gas phase and does hence provide a useful tool for computational catalysis. We discuss the application of the approach on three model systems for which exact semianalytical solutions exist and illustrate and quantify the importance of anharmonic vibrations, hindered rotations, and hindered translations (dissociation). Eventually, we apply the method to study the adsorption of small adsorbates in a zeolite (H-SSZ-13).