Department of Physics, University of Ioannina, Ioannina, Greece.
J Phys Chem A. 2011 May 5;115(17):4186-94. doi: 10.1021/jp2015947. Epub 2011 Apr 4.
We report on the interaction of alkyl-halide clusters with 35 ps and 20 fs laser pulses at λ = 266, 532, and 1064 nm and 400 and 800 nm, respectively. Particularly, we examine by means of time-of-flight mass spectrometry the intracluster photochemical processes, which give rise to the formation of molecular halogen ions. The efficiency of molecular halogen ion formation is found to depend strongly on the laser wavelength and pulse duration. The ionization/excitation schemes involve in both cases the multiphoton absorption by the clusters and the combined action of the laser and the intracluster electric field. Intracluster energy transfer processes seem to have a significant contribution to the molecular halogen ion formation in the ps domain, while in the fs region, this is probably facilitated by a rescattering process and/or by photon absorption. A physical mechanism for the interpretation of our experimental results is proposed.
我们报告了在 λ = 266、532 和 1064nm 以及 400 和 800nm 分别用 35ps 和 20fs 激光脉冲作用下，烷基卤化物团簇的相互作用。特别地，我们通过飞行时间质谱法研究了导致分子卤离子形成的团簇内光化学反应过程。发现分子卤离子形成的效率强烈依赖于激光波长和脉冲持续时间。在这两种情况下，离化/激发方案都涉及到多光子吸收和激光与团簇内电场的联合作用。在 ps 域中，团簇内能量转移过程似乎对分子卤离子的形成有很大的贡献，而在 fs 区域中，这可能是由再散射过程和/或光子吸收促进的。我们提出了一种用于解释实验结果的物理机制。
