论文标题
改进的冷凝相验型分子动力学的扭矩估计量
Improved torque estimator for condensed-phase quasicentroid molecular dynamics
论文作者
论文摘要
我们描述了对胶质分子动力学（QCMD）路径综合法的改进，该方法是最近开发用于计算凝聚相系统的红外光谱的。主要发育是对准分子上分子间扭矩的改进估计器。当应用于QTIP4P/F液态水和冰时，发现新的估计器可去除从库带中的人造25 cm $^{ - 1} $红色移动，以稍微增加液体中OH弹力带的强度，并减少先前在qCMD径向分布中注意到的小错误。我们还修改了绝热QCMD算法中使用的质量缩放，该算法允许分子动力学时间段四倍，从而将QCMD计算的费用降低到XTIP4P/F液体水的300 k和8次iCe 150 k的QCMD计算的费用到毛castesian centroid分子动力学的两倍。
We describe improvements to the quasicentroid molecular dynamics (QCMD) path-integral method, which was developed recently for computing the infrared spectra of condensed-phase systems. The main development is an improved estimator for the intermolecular torque on the quasicentroid. When applied to qTIP4P/F liquid water and ice, the new estimator is found to remove an artificial 25 cm$^{-1}$ red shift from the libration bands, to increase slightly the intensity of the OH stretch band in the liquid, and to reduce small errors noted previously in the QCMD radial distribution functions. We also modify the mass-scaling used in the adiabatic QCMD algorithm, which allows the molecular dynamics timestep to be quadrupled, thus reducing the expense of a QCMD calculation to twice that of Cartesian centroid molecular dynamics for qTIP4P/F liquid water at 300 K, and eight times for ice at 150 K.
