A simulation method for calculating the absolute entropy and free energy of fluids: application to liquid argon and water.
A simulation method for calculating the absolute entropy and free energy of fluids: application to liquid argon and water.
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计算流体绝对熵和自由能的模拟方法：应用于液氩和水。
DOI：
10.1073/pnas.0308197101
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Meirovitch,Hagai
中科院分区：
文献类型：
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作者：
White,RonaldP;Meirovitch,Hagai
假设扫描(HS)方法是通过分析蒙特卡罗(MC)或分子动力学技术获得的玻耳兹曼(Boltzmann)样品来计算绝对熵和自由能的一般方法。将HS应用于流体，通过将其原子逐渐添加到最初空的体积中，即通过使用转移概率(TPS)将它们放置在其位置来重建样品的每一种构型。在该过程的每个步骤中，体积被分为两个部分，已经访问的部分(“过去”)和“未来”部分，其中获得TP需要在存在冻结的过去的情况下计算关于未来部分的配分函数。在最近的出版物中，TPS是通过仅考虑部分未来来近似计算的。在这里，我们提出了一个“完整的HSMC”程序，其中TPS是根据在整个未来进行的MC模拟来计算的。将完整的HSMC方法应用于液态Ar体系和水的TIP3P模型，得到了很好的自由能计算结果，并与热力学积分的结果进行了比较。
The hypothetical scanning (HS) method is a general approach for calculating the absolute entropy and free energy by analyzing Boltzmann samples obtained by Monte Carlo (MC) or molecular dynamics techniques. With HS applied to a fluid, each configurationiof the sample is reconstructed by adding its atoms gradually to the initially empty volume, i.e., by placing them in their positions atiusing transition probabilities (TPs). At each step of the process, the volume is divided into two parts, the already visited part (the “past”) and the “future” part, where obtaining the TP requires calculating partition functions over the future part in the presence of the frozen past. In recent publications, the TPs were calculated approximately by taking into account only partial future. Here we present a “complete HSMC” procedure, where the TPs are calculated from MC simulations carried out over the complete future. The complete HSMC method is applied to systems of liquid argon and the TIP3P model of water, and very good results for the free energy are obtained, as compared with results obtained by thermodynamic integration.