Study of isomer-dependent reactions of organic molecular clusters

用双色多光子电离光谱结合质谱分析研究了C_6H_5F与NH_3和H_2O光解离范德华配合物簇内离子-分子反应。在不同异构体的选择性光电离作用下，C_6H_5F- nh_3的簇内反应分别为取代反应生成C_6H_5NH_2^+和解离反应生成C_6H_5F^+。观察了配合物的电离阈值光谱和反应产物的外观能。根据实验结果和计算出的同分异构体几何形状，讨论了反应的能量学。结果表明，C_6H_5NH_2^+的生成是由亲核取代反应引起的。还介绍了在H_2O配合物内发生的同分异构体依赖性反应，并讨论了它们的能量学与取代反应的势垒高度的关系。

Intracluster ion-molecule reactions of the photoionized van der Waals Complexes of C_6H_5F with NH_3 and with H_2O have been investigated by means of two-color multiphoton ionization spectroscopy in combination with mass analysis. Two different intracluster reactions of C_6H_5F-NH_3, the substitution reaction yielding C_6H_5NH_2^+ and the dissociation yielding C_6H_5F^+, were induced by the selective photoionization of different isomers of the complexes. Ionization threshold specra of the complexes and appearance energies of the reaction products were observed. Energetics of the reactions was discussed on the bases of the experimental results and the calculated geometries of the isomers. It was concluded that the nucleophilic substitution reaction is responsible for the C_6H_5NH_2^+ production. Isomer-dependent reactions occurring within the H_2O complexes were also presented, and their energetics was discussed in relation to a barrier height to the substitution reaction.