Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
J Phys Chem Lett. 2023 Jun 8;14(22):5127-5133. doi: 10.1021/acs.jpclett.3c00620. Epub 2023 May 30.
In this letter, a new approach to compute free energy differences (FEDs) between multiple thermodynamics states is introduced. The method directly uses energy probability densities, which can be extracted with high accuracy from equilibrium simulations to obtain FEDs. Methods in current use, such as Bennett acceptance ratio (BAR), its multistate generalization (MBAR), or the weighted histogram analysis method (WHAM), require iterative solution of nonlinear equations which are known to be slowly convergent. The equations providing MBAR FEDs are identical to those derived earlier by Souaille and Roux in a method that has become known informally as "binless WHAM". In contrast, we obtain FEDs by solution of linear equations. For the classic two-state problem, the statistical error of our method, solving linear equations, is shown analytically to match that of BAR under common conditions.
在这封信中，介绍了一种计算多个热力学态之间自由能差（FED）的新方法。该方法直接使用能量概率密度，可以从平衡模拟中以高精度提取，以获得 FED。当前使用的方法，如 Bennett 接受比（BAR）、其多态推广（MBAR）或加权直方图分析方法（WHAM），需要迭代求解非线性方程，已知其收敛速度较慢。提供 MBAR FED 的方程与 Souaille 和 Roux 早些时候在一种非正式称为“无 bin 的 WHAM”的方法中推导的方程相同。相比之下，我们通过求解线性方程来获得 FED。对于经典的两态问题，我们通过求解线性方程的方法的统计误差，在常见条件下，与 BAR 的统计误差进行了分析比较。
