Spectroscopic study on hydrogen-bonding and charge resonance interactions in aromatic cluser ions

本项目的目的是研究芳香分子作为发色体的团簇中的氢键相互作用。我们建立了脉冲场电离(PFI)-ZEKE光电子能谱仪。将中性团簇中的结构和氢键相互作用与团簇阳离子中的结构和氢键相互作用进行了比较，其中氢键相互作用与电荷共振相互作用相互竞争。我们观察了5-羟基邻苯二酮- co_2 /H_2O和9-羟基苯二酮- co_2 /H_2O簇的电子能谱，并结合多维势计算阐明了分子间相互作用对质子隧穿的影响。在4-氨基苯并腈- h_2o中已明确地鉴定出三个结构异构体。一个同分异构体的PFI-ZEKE光谱，其中水的氧原子与氨基质子成氢键，已经成功地观察到。我们研究了苯胺二聚体阳离子、苯-苯胺异二聚体阳离子和苯-苯甲醇异二聚体阳离子的稳定结构和分子间相互作用。苯胺二聚体离子和苯苯胺二聚体离子以氢键相互作用为主，不发生电荷共振相互作用，而苯苯醇二聚体离子有电荷共振相互作用。通过从头算和密度泛函理论计算得到了簇离子的稳定结构，并与簇离子的分子间相互作用相关联。我们已经证明，氢键相互作用对构成发色体的原子上的电荷密度非常敏感。

The purpose of this project is to investigate hydrogen bonding interaction in clusters involving an aromatic molecule as a chromophor. We have constructed an apparatus for pulsed field ionization (PFI)-ZEKE photoelectron spectroscopy. The structure and hydrogen bonding interaction in neutral clusters have been compared with those in cluster cations where the hydrogen bonding interaction competes with the charge resonance interaction. We have observed the electronic spectra of 5-hydroxytropolone-CO_2/H_2O and 9-hydroxyphenalenone-CO_2/H_2O clusters, and clarified the effects of intermolecular interaction on proton tunneling combined with multidimensional potential calculations. Three structural isomers have been clearly identified in 4-aminobenzonitrile-H_2O. The PFI-ZEKE spectrum of one isomer, where the oxygen atom of water is hydrogen-bonded to the amino proton, has been successfully observed. We have investigated stable structures and intermolecular interaction in the aniline dimer cation, benzene-aniline hetero-dimer cation, and benzene-benzylalcohol hetero-dimer cation. In the aniline dimer ion and benzene-aniline ion, the hydrogen-bonding interaction is predominant and no charge resonance interaction occurs, whereas the charge resonance interaction has been observed in the benzene-benzylalcohol dimer ion. The intermolecular interaction in the clusters ions has been correlated to the stable structures obtained by ab initio and density functional theory calculations. We have shown that the hydrogen bonding interaction is very sensitive to charge densities on the constitute atoms of the chromophor.