Motion of individual atoms and mesoscopic structural dynamics on non-equillibrium surfaces

非平衡表面上单个原子的运动和介观结构动力学

基本信息

批准号：
07454064
负责人：
ARUGA Tetsuya
金额：
$ 5.06万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07454064/
关键词：
surface alloy reaction dynamics scanning tunneling microscope coadsorption structural dynamics 表面超高真空 STM

项目摘要

In order to realize the direct observation of the dynamic motion of individual atoms and molecules on the non-equillibrium surfaces and to understand the underlying microscopic mechanism, we have developped a new variable-temperature scanned probe microscope. In order to study further on the surface dynamics, we have also conducted thermal desorption and high-resolution electron energy loss spectroscopy to investigate the ordering in the (NO+CO) coadsorption system on the Pd (100) surface.The scanned probe microscope developped in the present study can be operated under ultrahigh vacuum and at sample temperature from 100 to 1000K.Another important characteristic is its low-noise signal output. The vertical noise for the topographic imaging mode is 3pm (p-p), which enables the imaging of (100) and (111) surfaces of transition metals. This microscope can also be operated at tunneling current as low as 1pA, which enables imaging of low-conductivity materials such as organic crystals.The ordering in (NO+CO) /Pd (100) coadsorption system has been studied by low-energy electron diffraction, thermal desorption and vibrational spectroscopy preparatory to the application of the scanned probe microscope. We have found that NO and CO form stable mixed ordered phases and that an explosive CO2 formation reaction undergoes in the mixed ordered phases. A kinetic Monte Carlo simulation based on a lattice-gas model has been done to quantify NO-CO intermolecular interactions.We have also investigated on the H+H/Pd (100) reaction and found that the impinging H atoms force the preadsorbed H atoms to penetrate into Pd bulk (stamping absorption). The characteristics of the potential energy surface for the MH2 system was discussed.

为了实现对非平衡表面上单个原子和分子的动态运动的直接观察并了解其微观机制，我们开发了一种新型变温扫描探针显微镜。为了进一步研究表面动力学，我们还进行了热脱附和高分辨率电子能量损失光谱来研究Pd（100）表面上（NO+CO）共吸附体系的有序性。开发了扫描探针显微镜在本研究中，可以在超高真空和100至1000K的样品温度下运行。另一个重要特性是其低噪声信号输出。形貌成像模式的垂直噪声为 3pm (p-p)，可对过渡金属的 (100) 和 (111) 表面进行成像。该显微镜还可以在低至1pA的隧道电流下工作，从而能够对有机晶体等低电导率材料进行成像。通过低能电子研究了(NO+CO)/Pd(100)共吸附体系中的有序性衍射、热解吸和振动光谱为扫描探针显微镜的应用做好准备。我们发现NO和CO形成稳定的混合有序相，并且在混合有序相中发生爆炸性的CO2形成反应。基于晶格-气体模型的动力学蒙特卡罗模拟已经完成，以量化 NO-CO 分子间相互作用。我们还研究了 H+H/Pd (100) 反应，发现撞击的 H 原子迫使预吸附的 H 原子渗透到 Pd 块体中（冲压吸收）。讨论了MH2系统势能面的特性。