腺嘌呤-水分子团簇的理论研究
Theoretical investigation of the adenine-water clusters

利用密度泛函理论在B3LYP/6-311++G(d , p)基组水平上对C5H5N5？(H2O)m (m=1~3)进行了优化与振动频率计算，得到了团簇的六种稳定结构. 应用AIM程序计算了三种最稳定结构的氢键临界点的拓扑参数，结果表明，O―H…N氢键的形成使得O―H之间电子密度减小，伸缩振动频率减小，产生了红移；N―H…O氢键的形成使得N―H之间的电子密度减小，键的强度变弱，伸缩振动频率变小，发生了红移. 利用veda4软件对团簇C5H5N5？(H2O)m (m=0~3)的红外光谱的振动频率进行模式指认，并对部分振动频率进行了比较.
The C5H5N5？(H2O)m (m=1~3) molecule was optimized and vibrational frequency was calculated using density functional theory (DFT) at the B3LYP/6-311++G(d, f) level. AIM program was used to calculated critical points’ topological parameters of there most stable structures. The results show that strong red-shifted O―H…N hydrogen bond is attributed to the decrease of the O―H electron density and stretching vibrational frequency, meanwhile the red-shifted N―H…O hydrogen bond is attributed to the decrease of the N―H electron density and strenth and stretching vibrational frequency. The IR spectra of C5H5N5？(H2O)m (m=0~3) clusters were assigned by veda4 software and part of the vibration frequency were compared.