苯酚-水团簇C6H5OH（H2O）n（n=1～5）结构和光谱性质的密度泛函理论研究

Density functional theory study of the structural and spectral properties of C6H5OH（H2O）n（ n= 1-5） Clusters

利用密度泛函理论,在B3LYP/6-31+G(d,p)基组水平上对苯酚-水混合团簇C6H5OH(H2O)n(n=1~5)的可能构型进行了优化计算和频率分析,得到了团簇的能量最低构型,计算结果显示,团簇C6H5OH(H2O)n(n=2~5)的最稳定结构均为环状平面结构;分析讨论了苯酚-水混合团簇的红外振动光谱和拉曼光谱,对较强的谱峰进行了指认。红外光谱分析结果显示:振动强度较大的谱峰主要分布在高频(3 000 cm-1~3 500cm-1)区域,团簇C6H5OH(H2O)n(n=1~5)中振动强度最大的谱峰均归属为氢键O-H…O中的氢原子的伸缩振动;拉曼光谱分析发现:团簇C6H5OH(H2O)n(n=1~5)的拉曼活性在较高频段内表现较好,团簇C6H5OH(H2O)n(n=1~3,5)的拉曼最强振动峰均归属于苯酚环上C-H键的对称伸缩振动,团簇C6H5OH(H2O)4的拉曼最强振动峰均归属于团簇中的氢键O-H…O的对称伸缩振动。

Using the density functional theory,the possible configurations of the mixed phenol -water C6H5OH ( H2O) n( n = 1~5) clusters are optimized at the B3LYP /6-31+G( d,p) group level,and the lowest energy configu- rations of the clusters are obtained,The calculated results show that the most stable structures of C6H5OH( H2O) n( n = 2 ~5) clusters are the plane circular structure. The infrared and Raman spectrum of C6H5OH( H2O) n( n = 1~5) clus- ters are discussed and the stronger peaks appearing in infrared and Raman spectrum are assigned in this paper. The in- frared spectrum analysis shows that the spectral peaks with higher vibration intensity are mainly distributed in the high- er frequency ( 3 000 ~ 3 500 cm-1 ) band. The spectral peaks with the maximum vibration intensity in the C6H5OH ( H2O) n( n = 1~5) clusters are all assigned as stretching vibration of the hydrogen bond O-H…O. The Raman spec- trum analysis show that the C6H5OH( H2O) n( n = 1~5) clusters exhibit stronger Raman activity at the higher frequen- cy band. The strongest Raman vibrational peaks of the C6H5OH( H2O) n ( n = 1-3,5) clusters are attributed to the symmetric stretching vibration of the C-H bond on the phenol ring and the strongest Raman vibrational peaks of the C6H5OH( H2O) 4 cluster is attributed to symmetric stretching vibration of the hydrogen bond O-H…O.