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Study on Fundamental Processes and their Control of Condensation and Evaporation by Laser Excitation

激光激发凝聚与蒸发的基本过程及其控制研究

基本信息

批准号：
02402027
负责人：
KOTAKE Susumu
金额：
$ 19.71万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1992
项目状态：
已结题

项目摘要

The aim of the present study is to understand the fundamental process of condensation and evaporation from the standpoint of molecular clustering and the possibility of controlling the process with the thermal excitation method by using lasers. For the purpose, atomic/molecular beams of metal and nonmetal vapors were produced by the laser and electron-beam heating method. Clusters formed in the condensation process of these beams were irradiated by a laser beam to be excited on thermal level before striking a film condensate of which thickness were measured by a film thickness meter. The effects of the laser intensity and irradiation conditions on the features of film condensation also were investigated with a quadruple mass spectrometer and FTIR analyzer. It is found that the condensation rate can be changed by the laser irradiation. These effects of laser irradiation depend on the clustering process; the more clusterized the vapor atoms are, the more remarkable affect would be observed and the finer structure of the condensate could be obtained. The irradiation has little effect for vapors which are hardly clusterized. The laser of smaller wave lengths or higher energies has more intense effect on the condensation process. This can be attributed to the change in the intermolecular potential between molecules or atoms of clusters by laser irradiation rather than the change in their thermal energy. From these result, the possibility to control the fundamental process of condensation by laser irradiation has been evidenced.

本研究的目的是从分子团簇的角度理解凝聚和蒸发的基本过程，以及利用激光热激发方法控制这一过程的可能性。为此，通过激光和电子束加热方法产生了金属和非金属蒸气的原子/分子束。在这些光束的凝聚过程中形成的团簇被激光照射，在热水平上被激发，然后撞击薄膜凝聚物，膜厚计测量了凝聚物的厚度。利用四重质谱仪和红外光谱仪研究了激光强度和辐照条件对薄膜冷凝特性的影响。结果表明，激光辐照可以改变凝聚速率。激光辐照的这些效应依赖于凝聚过程，蒸气原子越团簇，影响越明显，凝聚体的结构越细小。辐射对几乎不成团的蒸汽影响不大。波长较小或能量较高的激光对凝聚过程的影响较大。这可以归因于激光照射下分子或原子间分子间势的变化，而不是它们的热能的变化。从这些结果中，证明了用激光照射来控制凝聚的基本过程的可能性。