Which quantum statistics-classical dynamics method is best for water?
Which quantum statistics-classical dynamics method is best for water?
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DOI：
10.1039/c9fd00077a
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发表时间：
2020-01-01
影响因子：
3.4
通讯作者：
Althorpe, Stuart C.
中科院分区：
文献类型：
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作者：
Benson, Raz L.;Trenins, George;Althorpe, Stuart C.
通过将量子玻尔兹曼统计与经典动力学相结合，在动力学模拟中包含核量子效应的方法有很多种。其中包括恒温环聚合物分子动力学（TRPMD），质心分子动力学（CMD），准质心分子动力学（QCMD）和线性化半经典初值表示（LSC-IVR）。在这里，我们通过计算水在气相、液相和冰相中的红外光谱（使用q-TIP 4P/F模型势），对这些方法进行了系统的比较。其中一些结果来自以前的工作，其中一些是新的（包括冰的LSC-IVR计算，以及将所有光谱扩展到以泛音和组合带为主的近红外区域）。我们的研究结果表明，QCMD是最好的方法再现基本的光谱中的跃迁，LSC-IVR给出了最好的整体描述的光谱（虽然有很大的误差，在弯曲基本带引起的零点能量泄漏）。TRPMD方法给出了与QCMD谱一致的阻尼谱，并且是迄今为止最便宜的方法。
There are a variety of methods for including nuclear quantum effects in dynamics simulations by combining quantum Boltzmann statistics with classical dynamics. Among them are thermostatted ring-polymer molecular dynamics (TRPMD), centroid molecular dynamics (CMD), quasi-centroid molecular dynamics (QCMD), and the linearised semi-classical initial value representation (LSC-IVR). Here we make a systematic comparison of these methods by calculating the infrared spectrum of water in the gas phase, and in the liquid and ice phases (using the q-TIP4P/F model potential). Some of these results are taken from previous work, and some of them are new (including the LSC-IVR calculations for ice, and extensions of all the spectra into the near-infrared region dominated by overtone and combination bands). Our results suggest that QCMD is the best method for reproducing fundamental transitions in the spectrum, and that LSC-IVR gives the best overall description of the spectrum (albeit with large errors in the bend fundamental band caused by zero-point-energy leakage). The TRPMD method gives damped spectra that line up with the QCMD spectra, and is by far the cheapest method.