非绝热量子动力学模拟方法及其在凝聚态体系中的应用  

Advances in methods and applications of nonadiabatic quantum dynamics simulation of condensed matters

作　　者：陈大强 游佩桅 聂正蔚 武娜 廉超 张萃 孟胜[1,2,3] Daqiang Chen;Peiwei You;Zhengwei Nie;Na Wu;Chao Lian;Cui Zhang;Sheng Meng(Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;Songshan Lake Materials Laboratory,Dongguan 523808,China;School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院物理研究所,北京凝聚态物理国家研究中心,北京100190 [2]松山湖材料实验室,东莞523808 [3]中国科学院大学物理科学学院,北京100049

出　　处：《科学通报》2021年第24期3088-3099,共12页Chinese Science Bulletin

基　　金：国家自然科学基金(91850120,1193403,11974400,11774396);国家高技术研究发展计划(2016YFA0300902);中国科学院B类战略性先导科技专项(XDB070301)资助。

摘　　要：密度泛函理论(density functional theory, DFT)可以准确地预测由电子和原子核组成的普通物质的基态电子结构,而当涉及量子体系含时演化的模拟时,比如模拟超快激光与分子或凝聚态体系相互作用的激发态动力学过程,就需要发展实时密度泛函理论(real-time time-dependent density functional theory, rt-TDDFT)和非绝热动力学相结合的新颖计算方法.本文介绍了基于rt-TDDFT的Ehrenfest动力学方法,并结合路径积分分子动力学提出了RPTDAP量子动力学方法. RP-TDAP方法引入了非绝热效应和原子核的量子效应,可以对电子波函数和原子核波包构成的耦合系统进行量子化动力学模拟.这些方法使我们不仅可以准确地理解激发态电子结构、电声相互作用、光致电荷传输、光化学反应等非绝热过程的内在机理,而且可以超越平均场理论给出一个全新的视角来描述原子核的量子行为.本文还应用这些方法研究了几个重要的非绝热动力学现象,说明这些方法可以广泛地用于复杂体系的量子激发超快动力学研究.First-principles molecular dynamics simulations, which can reveal the microscopic mechanisms and the macroscopic properties of molecules and condensed systems, have become a significant driving force in the development of physics. In the past decades, the ground state electronic properties of various materials can be accurately described using the firstprinciples method based on the Born-Oppenheimer approximation. However, in nonadiabatic processes, such as the ultrafast excited-state dynamics where laser interacts with molecules and condensed matters, the Born-Oppenheimer approximation evolving nuclear wave function on the ground state potential energy plane is no longer valid because of the nonnegligible nonadiabatic couplings between electrons and nuclei.In order to investigate the novel physical phenomena in nonadiabatic processes, many nonadiabatic molecular dynamics methods have been proposed, for instance, full quantum dynamics and mixed quantum-classical dynamics. When the nuclear quantum effects are trivial, the mixed quantum-classical dynamics is effective, which solves the time-dependent electron Schr?dinger equation and describes the motion of the nuclei in the form of Newtonian mechanics. Two methods based on the mixed quantum-classical dynamics, the fewest-switches trajectory surface-hopping method(FSSH) and Ehrenfest dynamics, have accepted much attention since they could be easily implemented and combined with real-time time-dependent density functional theory(rt-TDDFT) for high-precision calculations. The combination of quantum and classical dynamics reduces the computational cost and allows the applications for real materials.At low temperatures, the nuclear quantum effects, including quantum tunneling and zero-point vibrations, cannot be ignored. Ring-polymer molecular dynamics(RPMD) based on the imaginary-time path integral is widely used to consider the nuclear quantum effects, which describes the quantum behavior of atomic nuclei by sampling a larger number of quantum configurations and path

关 键 词：第一性原理 非绝热动力学 核量子效应 光激发 含时密度泛函理论 

分 类 号：O469[理学—凝聚态物理]