胸腺嘧啶-水分子团簇结构特性研究

The structural properties study on thymine-water molecules clusters

根据量子化学理论,应用Gaussian09W程序中密度泛函理论(DFT)B3LYP方法,在6-311++G(d,p)基组水平上,研究了胸腺嘧啶与水分子团簇C_5H_6N_2O_2·(H_2O)n(n=1~4)分子团簇的基态结构以及红外光谱.通过对C_5H_6N_2O_2·(H_2O)n(n=1~4)分子团簇的结构优化,获得了团簇最稳定的结构.AIM程序分析表明:分子团簇间形成了氢键,而且电子密度ρ的强弱也反映了红移和蓝移的大小.之后使用Veda4软件对C_5H_6N_2O_2·(H_2O)n(n=1~4)分子团簇红外光谱的振动频率进行了分析,并对振动频率进行了比较.最后,分析四种最稳定结构的分子团簇的红外光谱表明O-H…O和N-H…O氢键的形成使得O-H和N-H之间伸缩频率减小,发生了红移;O-H…N氢键使O-H之间的弯曲振动频率变大,发生了蓝移.

The ground state structure and infrared spectra of the C5H6N2O2·（H2O）n（n=1-4） clusters are calculated by density functional theory （DFT） at the B3LYP complex function in Gaussian09W. The stable structures of C5H6N2O2·（H2O）n clusters can be obtained by optimizing its structure. AIM program analysis shows that the formation of hydrogen bonds between clusters, and the intensity of electron density also reflects the size of the redshifted and blue -shifted. The vibrational infrared spectrum of C5H6N2O2·（H2O）n（n = 1 -4 ） clusters is analyzed by using the Veda4 and also compared the vibration frequency. The infrared spectra of the four most stable clusters molecules shows the formation of O - H…O or N - H…O H - bond makes the vibration frequency between O - H or N - H decrease and lead the vibration frequency red - shifted, while O - H…N H - bond makes the vibration frequency between O -H increase and lead the vibration frequency blue -shifted.