Physics Department, University of Houston, Houston, Texas 77204, USA.
J Chem Phys. 2011 Oct 14;135(14):144502. doi: 10.1063/1.3649679.
Water is often viewed as a collection of monomers interacting electrostatically with each other. We compare the water proton momentum distributions from recent neutron scattering data with those calculated from two electronic structure-based models. We find that below 500 K these electrostatic models, one based on a multipole expansion, which includes the polarizability of the monomers, are not able to even qualitatively account for the sizable vibrational zero-point contribution to the enthalpy of vaporization. This discrepancy is evidence that the change in the proton well upon solvation cannot be entirely explained by electrostatic effects alone, but requires correlations of the electronic states on the molecules involved in the hydrogen bonds to produce the observed softening of the well.
水通常被视为相互静电相互作用的单体集合。我们将最近的中子散射数据中的质子动量分布与基于两种电子结构模型计算的分布进行了比较。我们发现，在 500 K 以下，这些静电模型，包括单体极化率的多极展开模型，甚至无法定性地解释蒸发焓中相当大的振动零点贡献。这种差异表明，质子在溶剂化过程中势阱的变化不能仅用静电效应来完全解释，而是需要涉及氢键的分子的电子态的相关作用来产生观察到的势阱软化。
