关键词: 反应机理, 反应动力学, 氯, 钛, 激光化学, 分子束, 表面反应, 金属表面, 飞行时间谱

A mass selected time-of-flight (TOF) technique has been used to determine the mass distribution and velocity distribution of the reaction products of Cl2 molecular beam reacted with a Ti surface under pulsed UV (355nm), Vis(560nm) and near IR (1064nm) laser irradiation.the results show that the main reaction products, such as Ti, TiCl, TiCl3 and TiCl4are the same for different wavelength of laser radiations. the genuine Ti+ ions with high kinetic energy have been detected for the first time under the UV laser irradiation at high laser fluence. all of the TOf spectra for the Ti-contained chlorides can be fitted satisfactory with singly-or multi-component maxwell-boltzmann distribution.A mechanism with three steps, which mainly involves the dissociative chemisorption of the Cl2 molecules on the Ti surface, the consecutive reactions of the adsorbed Cl atoms to form TiClx(X=1～4) on the surface and the laser-induced desorption processes has been employed to explain the results of these laser-induced gas-surface reactions. it is found that the laserinduced thermaldesorption play a dominant role for the 1064nm laser irradiation, while competing nonthermal desorption processes are also important for the 355nm case.

Key words: REACTION MECHANISM, REACTION KINETICS, CHLORINE, TITANIUM, LASER CHEMISTRY, MOLECULAR BEAM, SURFACE REACTION, TIME OF FLIGHT SPECTRA