论文标题
统计机械近似，以更有效地确定小有机分子的多晶型差异差异
Statistical mechanical approximations to more efficiently determine polymorph free energy differences for small organic molecules
论文作者
论文摘要
在晶体结构预测（CSP）中，高度期望有效确定有机晶体的相对稳定性的方法。当前的方法包括使用静态晶格声子，准谐波近似（QHA）以及使用副本交换分子动力学（REMD）计算完整的热力学循环。我们发现，在使用REMD加热的29个系统中，有13个从实验重组为较低的能量最小的系统中，这是QHA无法捕获的现象。在这里，我们提出了一系列方法，这些方法是QHA和计算完整热力学周期之间准确性和费用的中间方法，可以节省42-80％的计算成本，并在此基准测试中引入相对较小的（0.16 +/- 0.04 kcal/mol）的误差，相对于完整的PSEUDOSUPEOSUPRACICALICALICALICALICALICALIC PARICANIC PATH方法。特别是，当筛选晶体多晶型物稳定性时，使用MD加权boltzmann加权REMD副本轨迹的谐波自由能似乎是QHA和完整热力学循环的适当中间体。
Methods to efficiently determine the relative stability of polymorphs of organic crystals are highly desired in crystal structure predictions (CSPs). Current methodologies include use of static lattice phonons, quasi-harmonic approximation (QHA), and computing the full thermodynamic cycle using replica exchange molecular dynamics (REMD). We found that 13 out of the 29 systems minimized from experiment restructured to a lower energy minima when heated using REMD, a phenomena that QHA cannot capture. Here, we present a series of methods that are intermediate in accuracy and expense between QHA and computing the full thermodynamic cycle which can save 42-80% of the computational cost and introduces, on this benchmark, a relatively small (0.16 +/- 0.04 kcal/mol) error relative to the full pseudosupercritical path approach. In particular, a method that Boltzmann weights the harmonic free energy of the trajectory of an REMD replica appears to be an appropriate intermediate between QHA and full thermodynamic cycle using MD when screening crystal polymorph stability.
