Finite-temperature infrared and Raman spectra of high-pressure hydrogen from first-principles molecular dynamics

作     者：Chunyi Zhang Cui Zhang Mohan Chen Wei Kang Zhuowei Gu Jianheng Zhao Cangli Liu Chengwei Sun Ping Zhang 

作者机构：HEDPS Center for Applied Physics and Technology College of Engineering Peking University Beijing 100871 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China Department of Physics Temple University Philadelphia Pennsylvania 19122 USA Collaborative Innovation Center of IFSA Shanghai Jiao Tong University Shanghai 200240 China Institute of Fluid Physics China Academy of Engineering Physics Mianyang 621900 China 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2018年第98卷第14期

页      面：144301-144301页

核心收录：

基　　金：NSFC-Guangdong Joint Fund National Natural Science Foundation of China, NSFC, (11625415, 21503019) National Natural Science Foundation of China, NSFC NSAF Joint Fund, (U1530258) NSAF Joint Fund Science Challenge Project, (TZ2016001) Science Challenge Project 

主　　题：First order phase transitions Lattice dynamics Solid-solid transformations Structural phase transition Molecular solids Density functional theory Infrared spectroscopy Molecular dynamics 

摘      要：Finite-temperature infrared and Raman spectra of theoretically proposed stable structures C2/c and Pc of high-pressure solid hydrogen are calculated from time correlation functions of dipole moments and polarizabilities extracted from first-principles molecular dynamics simulations. Calculated spectra are much improved compared with those obtained from density functional perturbation theory at zero temperature, which suggests the significance of finite-temperature effects in both spectra. The excellent agreement between the calculated spectra of the C2/c structure and experimental results supports the theory that C2/c is the structure of phase III. The high-frequency Raman vibron mode of the Pc structure is also well reproduced compared with experimental spectra. However, the energy of the low-frequency Raman vibron mode of the Pc structure is underestimated up to 16%. This suggests that the atomic structure of the strongly bonded layer in phase IV is well predicted, while the weakly bonded layer still differs from the real structure somehow. In addition, we find that diffusion in the weakly bonded layer of the Pc structure is strong and the layer displays several features of a two-dimensional liquid.