利用高灵敏的拉曼光谱系统地研究了由量子效应引起的轻水和重水的结构差异.测量了5—85℃的轻水和重水的拉曼光谱,明显地观察到两种水的拉曼光谱谱形的差别.使用全局拟合方法分析了所有谱图的谱形,结果显示在同一个温度下重水的局部结构要比轻水的结构有序,并且他们结构上的差异随着温度的升高而减少.另外计算了水结构差异的指标一温度漂移,从低温到高温时这个指标从28℃减小到18℃.这些结构差异表明量子效应在室温范围内也非常重要.我们还利用Vant’tHoff关系式分析了水分子相互作用能.这些结构上的细节可以帮助建立更加可靠的水模型.
The structure difference between light and heavy liquid water has been systematically in- vestigated by high precision Raman spectroscopy over the temperature range of 5-85℃. Distinct difference between the Raman spectral profiles of two different liquid waters is clearly observed. By analyzing the temperature-dependent Raman spectral contour using global fitting procedure, it is found that the micro-structure of heavy water is more ordered than that of light water at the same temperature, and the structure difference between the light and heavy water decreases with the increase of the temperature. The temperature off- set, an indicator for the structure difference, is determined to vary from 28 ℃ to 18 ℃ for the low-to-high temperature. It indicates that quantum effect is significantly not only at low temperature, but also at room temperature. The interaction energy among water molecules has also been estimated from van't Hoff's relationship. The detailed structural information should help to develop reliable force fields for molecular modeling of liquid water.