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Theory of Electronic and Nuclear Wavepacket Dynamic (Application to the structure deformation and electron transfer of molucular in laser field)

电子核波包动力学理论（在激光领域分子结构变形和电子转移中的应用）

基本信息

批准号：
12640484
负责人：
KONO Hirohiko
金额：
$ 2.18万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

To understand the ultrafast electronic dynamics in intense fields, we have been developing an efficient grid point method, the dual transformation method, for solving the time-dependent Schrodinger equation for the electronic degrees of freedom of a molecule. We have applied this method to small molecular systems such as H_2. The vibrational degree of freedom is also incorporated in the calculation of H^+_2 without resorting to the Born-Oppenheimer approximation.In a long wavelength case, for H_2, the localized ionic (bond) states H^+H^- and H^-H^+ appear alternately according to the optical cycle, through which tunnel ionization proceeds. After one-electron ionization from H_2, H^+_2 is prepared around the equilibrium internuclear distance of H_2. The bond distance of H^+_2 is then stretched by the applied field. With the help of ab initio molecular orbital calculations, we also demonstrate molecular structure deformations characteristic of intense-field dynamics such as symmetric two-bond stretching of CO_2 cations. The wave packet approach enables visualization of electron-nucleus correlation and two-electron dynamics in intense laser fields.Electronic motion can be controlled by adjusting the intensity, frequency, and pulse length. As an example, we have examined the electronic dynamics of H_2 in a short wavelength case (〜100 nm). Contrary to the long wavelength case, the electron pair is created near the proton at which the dipole interaction energy becomes higher. The nonstationary states H^+H^- and H^-H^+ appear alternately with a period inherent to the molecule even after the incident pulse has fully decayed. Ultrafast electron hopping between the nuclei can be controlled by a second pulse. Using this two-pulse scheme, we are able to enhance or suppress the ionization.

为了理解强场中的超快电子动力学，我们一直在发展一种有效的格点方法，即对偶变换方法，用于求解分子电子自由度的含时薛定谔方程。我们将这种方法应用于小分子体系，如H_2。在H_2的计算中也考虑了振动自由度，而不是采用Born-Oppenheimer近似。在长波长情况下，对于H_2，定域离子(键)态H^+H^-和H^-H^+根据光学循环交替出现，通过这个光学循环进行隧道电离。H_2的单电子电离后，在H_2的平衡核间距离附近生成H^+_2，H^+_2的键距被外加电场拉长。在从头算分子轨道计算的帮助下，我们还展示了强场动力学特征的分子结构形变，如CO_2离子的对称双键伸展。波包方法可以可视化强激光场中的电子-核关联和双电子动力学，可以通过调节强度、频率和脉冲长度来控制电子运动。作为例子，我们研究了在短波长(~100 nm)情况下H_2的电子动力学。与长波情况相反，电子对在偶极相互作用能变得更高的质子附近产生。即使在入射脉冲完全衰变之后，非定态态H^+H^-和H^-H^+仍以分子固有的周期交替出现。原子核之间的超快电子跳跃可以由第二个脉冲控制。利用这种双脉冲方案，我们能够增强或抑制电离。