Structure and vibrational spectra of small water clusters from first principles simulations
Structure and vibrational spectra of small water clusters from first principles simulations
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第一原理模拟中小水团簇的结构和振动光谱
DOI：
10.1063/1.3462278
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发表时间：
2010-07-07
影响因子：
4.4
通讯作者：
Yuan, Jianmin
中科院分区：
文献类型：
--
作者：
Kang, Dongdong;Dai, Jiayu;Yuan, Jianmin
用第一性原理分子动力学方法研究了（H2O）（n）（n = 2-5）团簇的结构和振动光谱.团簇结构随团簇大小的变化趋势表明，团簇中的水分子结合更紧密。振动光谱作为集群大小和温度的函数得到使用傅立叶变换的速度自相关函数。对基态簇合物的研究表明，随着簇合物尺寸的增大，由于簇合物的团簇化和氢键的增强，分子内OH伸缩振动峰蓝移，分子内OH伸缩振动峰红移.同时，分子内弯曲和自由OH伸缩模没有明显的位移，表明自由氢原子对局部成键环境不敏感。从二聚体到五聚体的温度依赖性振动光谱表现出类似的行为，表明热运动引起的光谱随温度的变化有显着的增宽。此外，不同的频带移动到不同的方向，其中Librational带移动到红色，而键合的OH伸缩带移动到蓝色，虽然蓝移是相当小的二聚体和三聚体。(C)2010年美国物理学会。[doi：10.1063/1.3462278]
The structure and vibrational spectra of (H2O)(n) (n = 2-5) clusters have been studied based on first-principles molecular dynamics simulations. Trends of the cluster structures with the cluster size show that water molecules in cluster are bound more tightly. The vibrational spectra as a function of cluster size and temperature are obtained using Fourier transformation of the velocity autocorrelation function. Results of the clusters in ground state show that when the cluster size increases, the librational peaks shift to blue and the bonded intramolecular OH stretching bands shift to red due to the clusterization and hydrogen-bond strengthening. Meanwhile, there are no significant shifts in the intramolecular bending and free OH stretching modes, indicating that the free hydrogen atoms are insensitive to the local bonding environment. The temperature-dependent vibrational spectra, which exhibit similar behaviors from the dimer to pentamer, show that there are significant broadenings of the spectra with temperature caused by thermal motions. Moreover, different bands shift to different directions, where librational bands shift to red while bonded OH stretching bands shift to blue, although the blueshifts are quite small for the dimer and trimer. (C) 2010 American Institute of Physics. [doi:10.1063/1.3462278]