Auer B M, Skinner J L
Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Wisconsin 53706, USA.
J Chem Phys. 2008 Dec 7;129(21):214705. doi: 10.1063/1.3012568.
An electronic structure/molecular dynamics approach, originally developed to describe the vibrational spectroscopy of the OH stretch of dilute HOD in liquid D(2)O, is applied to the vibrational sum-frequency spectroscopy of the liquid/vapor interface of this system. In both cases the OH stretch is effectively decoupled from the OD stretches, allowing it to act as a local probe of structure and dynamics. A mixed quantum/classical expression for the vibrational sum-frequency response that includes the effect of motional narrowing is used to calculate the resonant susceptibility. Despite being developed for the bulk liquid, our method works well for the surface in that the real and imaginary parts of the resonant susceptibility are in good agreement with experiment. We explore the nature of hydrogen bonding at the interface as well as its impact on the sum-frequency spectrum. It is found that the spectrum is dominated by single-donor molecules with a total of two or three hydrogen bonds.
一种最初为描述液态D₂O中稀HOD的OH伸缩振动光谱而开发的电子结构/分子动力学方法，被应用于该系统液/气界面的振动和频光谱研究。在这两种情况下，OH伸缩振动都能有效地与OD伸缩振动解耦，使其能够作为结构和动力学的局部探针。使用一个包含运动窄化效应的振动和频响应的混合量子/经典表达式来计算共振磁化率。尽管我们的方法是为体相液体开发的，但它在表面上也能很好地发挥作用，因为共振磁化率的实部和虚部与实验结果吻合良好。我们探究了界面处氢键的性质及其对和频光谱的影响。结果发现，光谱主要由总共具有两个或三个氢键的单供体分子主导。
