Communications: On artificial frequency shifts in infrared spectra obtained from centroid molecular dynamics: Quantum liquid water
Communications: On artificial frequency shifts in infrared spectra obtained from centroid molecular dynamics: Quantum liquid water
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DOI：
10.1063/1.3290958
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发表时间：
2010-01-21
影响因子：
4.4
通讯作者：
Marx, Dominik
中科院分区：
文献类型：
--
作者：
Ivanov, Sergei D.;Witt, Alexander;Marx, Dominik
质心分子动力学(CMD)是从路径积分模拟中提取近似量子动力学的一种流行方法。最近，我们发现CMD气相红外光谱显示出显著的伸缩峰的人为红移，这是由于有效质心势所印记的所谓的“曲率问题”。在这里，我们提供了证据，对于凝聚态，特别是对于液态水，CMD为高频振动产生了显著的人工红移，例如OH伸缩带。CMD方法固有的这种特殊行为解释了与经典频率相比，液态水伸展带的量子红移出人意料地大的部分原因，这在应用简单而粗略的“调和曲率修正”后得到了改善。
Centroid molecular dynamics (CMD) is a popular method to extract approximate quantum dynamics from path integral simulations. Very recently we have shown that CMD gas phase infrared spectra exhibit significant artificial redshifts of stretching peaks, due to the so-called "curvature problem" imprinted by the effective centroid potential. Here we provide evidence that for condensed phases, and in particular for liquid water, CMD produces pronounced artificial redshifts for high-frequency vibrations such as the OH stretching band. This peculiar behavior intrinsic to the CMD method explains part of the unexpectedly large quantum redshifts of the stretching band of liquid water compared to classical frequencies, which is improved after applying a simple and rough "harmonic curvature correction.".