吡啶-水团簇（C5H5N）n（H2O）m（n＝1～2，m＝1～4）结构和红外光谱的理论研究

摘要

利用密度泛函理论，在B3LYP/6‐311＋＋G（d ，p）基组水平上对吡啶‐水团簇（C5H5N）n（H2O）m（n＝1～2，m＝1～4）的可能构型进行全优化，得到了团簇的稳定结构；计算结果显示，在吡啶和水的二聚体中，稳定构型只有一种，没有发现通过π氢键（O— H…π）作用形成的团簇结构。为了研究各团簇结构的稳定性，在相同的基组水平上计算得到了各团簇构型的总能量和结合能，结果显示，对于团簇（C5 H5 N ）n （H2 O ）4（n＝1～2），团簇中的水分子形成四元环的结构要比形成三元环的结构稳定。对团簇的最高占据轨道与最低空轨道之间的能隙分析发现，团簇C5 H5 N （H2 O ）4的最低能量结构具有较高的稳定性，可能具有幻数结构；最后，分析讨论了吡啶‐水团簇的红外振动光谱，对较强的谱峰进行了指认。%Using density functional theory ,the possible geometrical structures of (C5 H5N)n(H2O)m(n=1~2 ,m=1~4) clus‐ters were optimized at the B3LYP/6‐311+ + G(d ,p) level and the stable structures were attained .For the dimer formed be‐tween C5 H5N and H2O ,the calculation result shows that there is only one stable structure and the configuration of cluster formed through πhydrogen bond (O—H⋯π) interaction was not found .In order to study the stability of the clusters ,the total energies and binding energies of the clusters were calculated at the same level of theory ,and the result shows that the four‐mem‐beredringstructuresofwatermoleculesin(C5H5N)n(H2O)4(n=1~2)clustersaremorestablethanstructuresofthetriatomic ring of water molecules .The lowest energy structure of the C5 H5 N(H2 O)4 cluster is more stable than the others and is probably a magic number structure by the analysis to the energy gap between HOMO and LUMO . At the end , the IR spectra of (C5H5N)n(H2O)m(n=1~2 ,m=1~4) clusters were analysed and the stronger peaks appearing in infrared spectra were as‐sig ned .