氨水质子化团簇NH4^＋（H2O）4的结构和红外振动光谱的研究

STRUCTURES AND IR HARMONIC VIBRATION SPECTURE OF PROTONATED AMMONIA WATER CLUSTERS

用密度泛函B3LYP方法，分别在6—31G（d）和6—311＋＋G（d，p）水平上逐步对质子化氨水团簇NH4^＋（H2O）4进行结构优化和频率计算，得到NH4^＋（H2O）4团簇的九种可能稳定构型及其相对应的能量．并用同样的方法对团簇的红外振动光谱进行了研究，通过对红外振动光谱中的谱峰位置与振动模式之间的关系的分析发现，质子化团簇的振动光谱普遍较中性团簇的振动光谱复杂．

The stable structures and IR harmonic vibration spectra of protonated ammonia water cluster NH4^＋（H2O）4 are calculated at the 6 -31G（d） level by means of density functional theory（B3LYP）. The corresponding energies are analyzed at the level B3LYP/6 -311 ＋ ＋ G（d,p） in order to obtain more accurate result, and the IR harmonic vibrational spectra of the most stable structures of protonated ammonia cluster NH4^＋（H2O）4 are studied in the same method. With the analysis to the relation between the position of the peaks and their corresponding vibrational modes of IR harmonic vibrational spectra, it is found that the IR harmonic vibrational spectra of NH4^＋（H2O）4 are more complex than those of NH3 （H2O）4.