Département de Chimie, Ecole Normale Supérieure, UMR CNRS-ENS-UPMC, Paris, France.
J Chem Phys. 2011 Feb 28;134(8):084303. doi: 10.1063/1.3521273.
We study the vibrational properties of the protonated water dimer and its deuterated forms at room temperature. Molecular dynamics simulations within the empirical valence bond (EVB) model are used to generate the vibrational spectra that are interpreted using the effective modes analysis (EMA). Quantum effects are taken into account through an effective parametrization of the EVB model. EMA allows for the assignment of the bands in the 1000 - 2000 cm(-1) region of the protonated water dimer from the molecular dynamics trajectory. It is then found that although this system is very anharmonic the two main bands in this spectral region arise from a linear coupling between the asymmetric OH(+)O stretch and asymmetric bend of the two water molecules. This mixing explains the simulated band shifts upon isotopic substitution of the central proton or of the hydrogens of the two water molecules.
我们研究了室温下质子化水二聚体及其氘代形式的振动特性。采用经验价键 (EVB) 模型的分子动力学模拟生成了振动光谱，并用有效模式分析 (EMA) 进行了解释。通过对 EVB 模型的有效参数化考虑了量子效应。EMA 允许从分子动力学轨迹中分配质子化水二聚体在 1000-2000 cm(-1) 区域的带。然后发现，尽管该系统非常非谐，但该光谱区域的两个主要带是由两个水分子的不对称 OH(+)O 伸展和不对称弯曲之间的线性耦合引起的。这种混合解释了在中心质子或两个水分子的氢的同位素取代时模拟带的位移。
