Prediction of accurate anharmonic experimental vibrational frequencies for water clusters, (H2O)n, n=2-5
Prediction of accurate anharmonic experimental vibrational frequencies for water clusters, (H2O)n, n=2-5
复制标题
DOI：
10.1021/jp054958y
复制
发表时间：
2006-01-12
影响因子：
2.9
通讯作者：
Shields, GC
中科院分区：
文献类型：
--
作者：
Dunn, ME;Evans, TM;Shields, GC
通过对MP2/Aug-cc-pVTZ计算和实验非谐频率的比较，预测了由2-5个水分子组成的水分子团簇的精确非谐实验振动频率。分子内模式采用HF/6-31G*标度频率，分子间模式采用非谐频率，对水二聚体和三聚体的计算结果与实验符合得很好，与昂贵的非谐MP2计算结果一样好。水三聚体、环状C-I和S-4四聚体和环状五聚体的红外光谱在500~800 cm(-1)和3400~3700 cm(-1)之间均有独特的吸收峰。在合适的实验条件下，利用高分辨率红外光谱可以唯一地识别这些不同的团簇。
Accurate anharmonic experimental vibrational frequencies for water clusters consisting of 2-5 water molecules have been predicted on the basis of comparing different methods with MP2/aug-cc-pVTZ calculated and experimental anharmonic frequencies. The combination of using HF/6-31G* scaled frequencies for intramolecular modes and anharmonic frequencies for intermolecular modes gives excellent agreement with experiment for the water dimer and trimer and are as good as the expensive anharmonic MP2 calculations. The water trimer, the cyclic C-i and S-4 tetramers, and the cyclic pentamer all have unique peaks in the infrared spectrum between 500 and 800 cm(-1) and between 3400 and 3700 cm(-1). Under the right experimental conditions these different clusters can be uniquely identified using high-resolution IR spectroscopy.