Theoretical Study on Spatial and Temporal Heterogeneous Dynamics in Condensed Phases

我们一直在研究时空非均匀动力学中的涨落和松弛。我们发展了一种计算三阶非线性光谱的第一性原理方法。我们解决了液态水和冰的涨落和能量松弛动力学以及分子间动力学，并为最近实验中观察到的水中的分子间动力学提供了分子图像。我们用三次关联函数研究了非均相动力学。结果表明，新引入的三时间相关函数对传统二时间相关函数所隐藏的大范围内相关运动的非均匀动力学和耦合是敏感的。此外，我们还利用分子动力学模拟计算的复热容量研究了水的恒压热容C_P随温度的反常变化。本研究揭示了随着温度的降低，碳磷急剧增加的时空能量起伏。

We have been investigating fluctuations and relaxations in spatial and temporal heterogeneous dynamics. We developed a first-principal method to calculate third-order nonlinear spectroscopy. We resolved the fluctuations and energy relaxation dynamics intermolecular dynamics of liquid water and ice and presented a molecular picture for the intermolecular dynamics in water which have been observed in recent experiments. We investigated heterogeneous dynamics by means of three-time correlation functions. As a result, it was revealed that the newly introduced three-time correlation function is sensitive to the heterogeneous dynamics and couplings of correlated motions over a wide range of time scales which are hidden in the conventional two-time correlation functions. In addition to these studies, we studied the anomalous temperature dependence of constant pressure heat capacity, C_P, of water by using the complex heat capacity calculated from molecular dynamics simulation. The present study revealed the spatial and temporal energy fluctuation that produces sudden increase in C_P with decreasing temperature.