Voyiatzis Evangelos, Stepanyan Roman
DSM, Applied Science Center, P.O. Box 1066, 6160 BB Geleen, The Netherlands.
J Phys Chem B. 2022 Sep 15;126(36):7027-7036. doi: 10.1021/acs.jpcb.2c03620. Epub 2022 Aug 31.
Sensitivity analysis of the ReaxFF potential for two Si and SiO systems has been carried out using the method of Morris. The goal is to identify the most important force field parameters for selected properties. Thus, a clearer physical interpretation for some of the parameters can be obtained while the ranking of the parameters per magnitude of sensitivity for each property facilitates the development of parametrizations with improved quality. The parameters related to the σ-bond and van der Waals interactions have the greatest influence on the properties of the cubic diamond Si phase. Counterintuitively, parameters which have an impact on mechanical properties, such as the ones for ππ-bonds, do not influence pressure and vice versa. For the β-cristobalite SiO phase, the Si-O cross-interaction parameters have stronger effect on all properties than the Si-Si and O-O elemental ones. This dependence is attributed to the tetrahedral structure of the SiO phase. Regarding the sensitivity measures, the mean of the absolute values of the elementary effect (EE) distribution correlates with the standard deviation of the EE distribution in all cases; it quantifies the sensitivity of a property on a parameter and the cross-correlation of the parameter with the other ones. The mean of the EE distribution has a poor performance and its use should be avoided. It is also argued that performing a sensitivity analysis before force field optimization might greatly enhance the efficiency of the optimization methods by considering a two-step procedure, where the most relevant parameters are optimized first.
已使用莫里斯方法对两个硅（Si）和二氧化硅（SiO）系统的反应分子动力学（ReaxFF）势进行了敏感性分析。目的是确定所选性质中最重要的力场参数。因此，对于某些参数可以获得更清晰的物理解释，同时按每个性质的敏感性大小对参数进行排序有助于开发质量更高的参数化方法。与σ键和范德华相互作用相关的参数对立方金刚石硅相的性质影响最大。与直觉相反，对机械性能有影响的参数，如与ππ键相关的参数，对压力没有影响，反之亦然。对于β-方石英SiO相，Si-O交叉相互作用参数对所有性质的影响比Si-Si和O-O元素自身的相互作用参数更强。这种依赖性归因于SiO相的四面体结构。关于敏感性度量，在所有情况下，基本效应（EE）分布绝对值的平均值与EE分布的标准差相关；它量化了一个性质对一个参数的敏感性以及该参数与其他参数的交叉相关性。EE分布的平均值性能较差，应避免使用。还有人认为，在力场优化之前进行敏感性分析，通过考虑两步程序，即首先优化最相关的参数，可能会大大提高优化方法的效率。
