Theoretical Study of Electron Correlation Effects on Dynamical Phenomena at Surfaces

电子相关效应对表面动力学现象的理论研究

• 批准号: 07650034
• 负责人: OKIJI Ayao
• 金额: $ 1.6万
• 依托单位: WAKAYAMA NATIONAL COLLEGE OF TECHNOLOGY (1997)Osaka University (1995-1996)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650034/
• 关键词: photo-induced desorption; ultrafast electron dynamics; associative desorption; orientation alignment; cartwheel-type rotation; dynamical quantum filter; helicopter-type rotation; spectroscopy in time domain; 超短レーザー光パレス; ヘリプタ型回転; 解離散乱; 水素分子; 分子

In order to clarify the mechanism behind dynamical processes at solid surfaces such as dissociative adsorption and associative desorption of hydrogen, photo-stimulated desorption of adsorbed molecules, quantum transport phenomena, and transient response of surface electron system to ultrashort laser pulses, it is necessary to have an aocurate knowledge of potential energy surfaces, excited as well as the ground states of electron system, and the enterrelation between electronic transitions and state-changes of molecular motion. With this in mind, theoretical studies on dynamical processes at solid surfaces have been done. The obtained results are summarized as follows.1. Making stress on the spatial as well as temporal locality of electronic excitations, we have investigated trajectories of molecules in photo-stimulated desorption. On the basis of the obtained results, dependences of the desorption probability on energy, time duration, and penetration depth of laser pulses are clarifie … More d.2. As a dynamical quantum filter, the orientation dependent activation barrier can select rotational states of molecules which attempt to pass through the barrier and to desorb. On the way toward the vacuum from the barrier (transition region), molecules are rotationally excited, de-excited, or retain rotational states at the transition region. It is found that molecules rotationally de-excited as well as those retaining rotational states at the transition region do helicopter-like rotational motion, and that molecules rotationally excited do cartwheel-like rotational motion.3. An expression of time-resolved two-photon photoemission spectrum is derived from a microscopic point of view. On the basis of the obtained results, it is clarified how the information about the lifetime of intermediate states at surfaces can be obtained by the cross correlation trace. Furthermore, the effects of inter-band excitations on the cross correlation trace are clarified.4. The electron correlation effects on electron transport phenomena in an atom-sized contact between an STM-tip and a metal surface are investigated with the aid of the Hubbard Hamiltonian. It is shown that intra-and inter-subband scattering of traveling electrons are induced by Coulomb interacion at finite-temperatures and that the step wise variation of the conductance as a function of the stretching distance of the STM-tip is considerably affected. Less

为了阐明固体表面动力学过程背后的机制，如氢的解离吸附和缔合解吸、吸附分子的光激解吸、量子输运现象以及表面电子系统对超短激光脉冲的瞬态响应，有必要对电子系统的势能面、激发态和基态有一个准确的认识，以及电子跃迁与分子运动状态变化之间的内在联系。考虑到这一点，固体表面动力学过程的理论研究已经完成。主要研究结果如下：1.强调电子激发的空间和时间局部性，我们研究了光刺激脱附中分子的轨迹。在此基础上，阐明了脱附几率与激光脉冲能量、持续时间和穿透深度的关系 ...更多信息 D.2.作为一个动态量子滤波器，取向依赖激活势垒可以选择试图通过势垒和解吸的分子的旋转状态。在从势垒（过渡区）到真空的过程中，分子被旋转激发、去激发或在过渡区保持旋转状态。研究发现，旋转退激态分子和在过渡区保持旋转态的分子做类陀螺旋转运动，而旋转激发态分子做类侧手翻旋转运动.从微观角度导出了时间分辨双光子光电子能谱的表达式。在所得结果的基础上，阐明了如何利用互相关迹获得表面中间态寿命的信息。进一步阐明了带间激励对互相关轨迹的影响.利用Hubbard哈密顿量研究了STM针尖与金属表面原子级接触中电子输运现象的电子关联效应。结果表明，在有限的温度下，库仑相互作用引起的子带内和子带间的散射的旅行电子和作为STM尖端的拉伸距离的函数的电导的逐步变化是相当大的影响。少

项目成果

H.Kasai: "Effects Electronic Excitations on Translational Energy Distribution of Ions Scattered by Metal Surfaces" J.Phys.Soc.Jpn.64. 4308-4316 (1995)

H.Kasai：“电子激发对金属表面散射离子的平移能量分布的影响”J.Phys.Soc.Jpn.64。

H.Kasai: "Effects of Electronic Excitations on Translational Energy Distribution of Ions Scattered by Metal Surfaces" J.Phys.Soc.Jpn. 64. 4308-4316 (1995)

H.Kasai：“电子激发对金属表面散射离子平移能量分布的影响”J.Phys.Soc.Jpn。

H.Kasai: "On the Molecular Orientation Dependence of Dynamical Processes on Solid Surfaces : Dissociative Adsorption and Scattering" Springer Series in Solid-State Sciences. 121. 99-111 (1996)

H.Kasai：“论固体表面动力学过程的分子取向依赖性：解离吸附和散射”固体科学中的施普林格系列。

H.Tsuchiura: "A Model Calculation for Photo-Stimulated Desorption" J.Phys.Soc.Jpn. 66. 2805-2810 (1997)

H.Tsuchiura：“光刺激解吸的模型计算”J.Phys.Soc.Jpn。

H.Kasai: "A Microscopic Theory of Desorption Induced by Electronic Transitions" Surf.Sci.368. 214-222 (1996)

H.Kasai：“电子跃迁引起的解吸微观理论”Surf.Sci.368。