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Computer Studies on Interactions of Ionized Cluster Beam With Solids

电离簇束与固体相互作用的计算机研究

基本信息

批准号：
01550254
负责人：
YAMAMURA Yasunori
金额：
$ 1.28万
依托单位：
Okayama University of Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01550254/
关键词：
Monte Carlo simulation Binary collision approximation Cluster ion Energy spectrum Cluster impact fusion Many body effect Time-evolutional simulation Ionized cluster beam deposition モンテカルロシミュレ-ション計算機シミュレ-ションクラスタ-イオンビ-ム蒸着

项目摘要

In order to investigate the interaction of an ionized cluster beam with solids, we have developed the time-evolution Monte Carlo simulation codes DYACOCT^<1)> and DYACAT^<2)>. The DYACAT code can be applied to the investigation of the cluster-impact phenomenon in an amorphous solid, and the DYACOST code to that in a crystalline solid. In these programs which are based on the binary collision approximation, trajectories of ions and recoil atoms are followed dynamically. In order to overcome the difficulties of the binary collision approximation of a low-energy projectile, many body encounter are numerically solved by the molecular dynamics method, where a projectile collides at the same time with many atoms within its collision diameter. These codes can be successfully applied to the sputtering phenomena^<3)>, radiation damage^<4,5)> and the cluster-impact phenomena^<,2,6,7)>.In order to investigate the low-energy cluster-impact phenomenon, the ionized (Ag)_n cluster beam (n being 100 t … More o 500) with energies of a few eV/atom are bombarded on an amorphous carbon surface. The energy-dependencies and the size dependencies of the ionized cluster impact phenomena have been studied. The ionized Ag cluster beam are bombarded on amorphous carbon surface. It is found that the mechanism of ionized cluster beam deposition (ICBD) can be divided into three stages, i. e., high surface density formation, reflection by the high surface density and collisional spike in the cluster due to the collision between virgin atoms in the upper part of cluster and reflected atoms from the dense surface. Thus, in the case of a cluster beam with energy of a few eV/atom the many body effect is essential and the bombarding energy is converted to the surface migration energy. Another important conclusion is that the larger cluster has the higher ICBD efficiency if the incident energy per atom is enough small.In order to investigate the high-energy cluster-impact phenomenon, the ionized (Ag)n and (Al)n cluster beam (n being 100 to 500) with energies of a few keV/atom are bombarded on amorphous carbon and gold targets, respectively. It is found that one of most important effects in the high-energy cluster-impact phenomena is the interaction between the constituent atoms in the cluster and that in the case of a cluster beam with energy of keV/atom the cluster-impact phenomena depends so much on the mass ratio M_1/M_2. when M_1 < M_2, some constituent atoms are accelerated up to three times larger energies than the incident energy/atom. One of the most important effects in the cluster-impact phenomena is the interaction between the constituent atoms in the cluster. Less

为了研究电离簇束与固体的相互作用，我们开发了时间演化蒙特卡罗模拟代码DYACAT^< 1)>和DYACAT^<2)>。DYACAT程序可用于研究非晶固体中的团簇撞击现象，DYACOST程序可用于研究结晶固体中的团簇撞击现象。在这些基于二元碰撞近似的程序中，离子和反冲原子的轨迹被动态跟踪。为了克服低能弹丸二元碰撞近似的困难，采用分子动力学方法对弹丸与其碰撞直径内的多个原子同时碰撞的多体碰撞进行了数值求解。这些代码可以成功地应用于溅射现象^<3)>，辐射损伤^<4,5)>和团簇撞击现象^<,2,6,7)>。为了研究低能团簇撞击现象，将能量为几eV/原子的离子化（Ag）_n团簇束（n = 100 ~ 500）轰击在非晶碳表面。研究了电离团簇撞击现象的能量依赖关系和尺寸依赖关系。离子化银簇束在非晶碳表面轰击。发现电离团束沉积（ICBD）的机理可分为三个阶段，即高表面密度形成阶段、高表面密度反射阶段和团簇上部的未原子与稠密表面反射原子碰撞产生的碰撞尖峰阶段。因此，对于能量为几eV/原子的簇束，多体效应是必不可少的，轰击能转化为表面迁移能。另一个重要的结论是，如果每个原子的入射能量足够小，则更大的簇具有更高的ICBD效率。为了研究高能团簇撞击现象，将能量为几keV/原子的（Ag）n和（Al）n离子束（n为100 ~ 500）分别轰击在非晶碳和金靶上。发现团簇碰撞现象中最重要的影响之一是团簇中组成原子之间的相互作用，对于能量为keV/原子的团簇束，团簇碰撞现象很大程度上取决于质量比M_1/M_2。当M_1 < M_2时，一些组成原子被加速到比入射能量/原子大三倍的能量。在团簇碰撞现象中最重要的影响之一是团簇中组成原子之间的相互作用。少