Nahler N Hendrik, Farnik Michal, Buck Udo, Vach Holger, Gerber R Benny
Max-Planck-Institut fur Stromungsforschung, Bunsenstrasse 10, 37073 Gottingen, Germany.
J Chem Phys. 2004 Jul 15;121(3):1293-302. doi: 10.1063/1.1763570.
Photodissociation experiments were carried out at 193 nm for single HCl molecules which are adsorbed on the surface of large Ar n clusters and small (HCl)m complexes which are embedded in the interior of these clusters. For the surface case the size dependence is measured for the average sizes n=140-1000. No cage exit events are observed in agreement with the substitutional position of the molecule deeply buried in the outermost shell. This result is confirmed by a molecular dynamics simulation of the pickup process under realistic conditions concerning the experiment and the interaction potentials. The calculations of the dissociation process employ the surface hopping model. For the embedded case the average sizes covered are m=3 and 6 and n=8-248. The kinetic energy of the H atom fragments is measured exhibiting peaks at zero and around 2.0 eV which mark completely caged and unperturbed fragments, respectively. The ratio of theses peaks strongly depends on the cluster size and agrees well with theoretical predictions for one and two closed icosahedral shells, in which the nonadiabatic coupling of all states was accounted for.
对吸附在大尺寸Arₙ团簇表面的单个HCl分子以及嵌入这些团簇内部的小尺寸(HCl)ₘ络合物进行了193nm的光解离实验。对于表面情况，测量了平均尺寸n = 140 - 1000时的尺寸依赖性。未观察到笼逃逸事件，这与深埋在最外层壳层中的分子的替代位置一致。在与实验和相互作用势相关的实际条件下对拾取过程进行的分子动力学模拟证实了这一结果。解离过程的计算采用表面跳跃模型。对于嵌入情况，覆盖的平均尺寸为m = 3和6以及n = 8 - 248。测量了H原子碎片的动能，在零和约2.0eV处出现峰值，分别标记完全被笼住和未受干扰的碎片。这些峰值的比率强烈依赖于团簇尺寸，并且与考虑了所有状态的非绝热耦合的一个和两个封闭二十面体壳层的理论预测非常吻合。
