Self-interaction-free time-dependent density-functional theory for molecular processes in strong fields:: High-order harmonic generation of H2 in intense laser fields -: art. no. 023411
Self-interaction-free time-dependent density-functional theory for molecular processes in strong fields:: High-order harmonic generation of H2 in intense laser fields -: art. no. 023411
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DOI：
10.1103/physreva.63.023411
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发表时间：
2001-02-01
影响因子：
2.9
通讯作者：
Chu, SI
中科院分区：
文献类型：
--
作者：
Chu, X;Chu, SI
本文提出了一种用于强激光场中多电子分子系统的多光子过程的非微扰处理的自相互作用无时变密度泛函理论。采用时变优化有效势（OEP）方法，引入显式自相互作用校正（SIC）项，构造了具有适当的短、长势的时变交换相关（xc）能量势。所得到的时变OEP/SIC方程在结构上与时变Hartree-Fock方程相似，但通过与轨道无关的单粒子局域时变再势包含了多体效应。介绍了一种精确、高效求解双中心双原子分子体系TDDFT/OEP-SIC方程的数值时间传播技术。这一过程涉及使用广义伪谱法对长球面坐标中的哈密顿量进行非均匀最优网格离散化，并在电子轨道波函数的时间发展的能量表示中使用分裂算子格式。高精度的随时间变化的波函数可以通过这个程序获得，只使用少量的空间网格点。应用该理论详细研究了强脉冲激光场中H-2分子的高次谐波产生过程。特别注意利用小波时频分析的方法来探索HHG的频谱和时间结构。结果揭示了HHG的光谱和时间精细结构的惊人细节，为不同能量状态下HHG的详细机制提供了新的见解。
We present a self-interaction-free time-dependent density-functional theory (TDDFT) for nonperturbative treatment of multiphoton processes of many-electron molecular systems in intense laser fields. The time-dependent exchange-correlation (xc) energy potential with proper short- and long-range potential is constructed by means of the time-dependent optimized effective potential (OEP) method and the incorporation of an explicit self-interaction-correction (SIC) term. The resulting time-dependent OEP/SIC equations are structurally similar to the time-dependent Hartree-Fock equations, but include the many-body effects through an orbital-independent single-particle local time-dependent re potential. A numerical time-propagation technique is introduced for accurate and efficient solution of the TDDFT/OEP-SIC equations for two-center diatomic molecular systems. This procedure involves the use of a generalized pseudospectral method for nonuniform optimal grid discretization of the Hamiltonian in prolate spheroidal coordinates and a split-operator scheme in the energy representation for the time development of the electron orbital wave functions. High-precision time-dependent wave functions can be obtained by this procedure with the use of only a modest number of spatial grid points. The theory is applied to a detailed study of high-order harmonic generation (HHG) processes of H-2 molecules in intense pulsed laser fields. Particular attention is paid to the exploration of the spectral and temporal structures of HHG by means of the wavelet time-frequency analysis. The results reveal striking details of the spectral and temporal fine structures of HHG, providing new insights regarding the detailed HHG mechanisms in different energy regimes.