Development of time-dependent density functional theory for electronic and nuclear degrees of freedom : Investigation of structural deformation of molecules in intense laser fields

点击翻译按钮获取中文摘要

We developed a dual transformation method that is applicable to multicomponent density functional theory. The model of a multicomponent system is chosen to be H_2^+. The energy and the geometry of the ground state are calculated by using the finite difference method based on multicomponent density functional theory. The results obtained were compared with those obtained from the Born-Oppenheimer approximation and those obtained by exact treatment. The real-time dynamics of H_2^+ are also demonstrated. The results obtained are discussed and compared with the exact solution. The importance of the dynamic correlation effect between nuclei and an electron is clearly shown. We also present a nucleus-electron gas model to estimate the nucleus-electron correlation energy. The expression of the effective interaction between nucleus and electron in the framework of the random-phase approximation is derived. We find that the attractive interaction between nucleus and electron can be shielded. Th … More e expression of the perturbation energy within the ladder approximation is also derived. We present a numerical procedure to calculate the correlation energy and the correlation potential between nucleus and electron, and estimate the nucleus-electron correlation potential.To examine the validity of the above methods, we developed a reference method, namely, the time-dependent adiabatic state approach, in which the electronic and nuclear dynamics in a near-infrared field is described in terms of time-dependent adiabatic potentials and nonadiabatic transitions due to temporal change in the laser electric field. The properties of the adiabatic states of polyatomic molecules can be calculated by ab initio molecular orbital methods. We applied the proposed approach to dynamics of CO_2 in near-infrared intense fields and revealed that in the CO_2^<2+> stage, simultaneous symmetric two-bond stretching followed by the occurrence of a large-amplitude bending motion is induced by an intense field. We also reported the results of theoretical investigation of experimentally observed selective cleavage of C-O and C-C bonds of ethanol in intense laser fields. Less