Nonequilibrium molecular dynamics simulations of vibrational energy relaxation of HOD in D2O
Nonequilibrium molecular dynamics simulations of vibrational energy relaxation of HOD in D2O
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DOI：
10.1063/1.3126781
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发表时间：
2009-05-07
影响因子：
4.4
通讯作者：
Vikhrenko, Vyacheslav S.
中科院分区：
文献类型：
--
作者：
Kandratsenka, Alexander;Schroeder, Joerg;Vikhrenko, Vyacheslav S.
采用经典非平衡态分子动力学模拟方法研究了氘代水溶液中HOD的振动能量弛豫。采用灵活的SPC/E模型来描述D2O溶剂的分子间相互作用和分子内势能。一个更准确的分子内电位用于HOD。我们的结果为OH拉伸，OD拉伸，HOD弯曲振动弛豫时间分别为2.7，0.9和0.57 ps。激发OH伸缩模式的主要弛豫途径涉及到弯曲振动的过渡。这些结果与最近的半经典Landau-Teller计算一致。然而，与以前的工作相反，我们观察到弯曲和OH伸缩模式与HOD旋转的强耦合。结果，几乎一半的总振动能量通过HOD旋转传递到浴。同时，最有效的受体模式是D2O旋转，表明共振振动到振动能量转移的重要性。我们还发现显着的振动激发的D2O弯曲模式的D2O溶剂的V-V能量转移从HOD弯曲模式。
Vibrational energy relaxation of HOD in deuterated water is investigated performing classical nonequilibrium molecular dynamics simulations. A flexible SPC/E model is employed to describe the intermolecular interactions and the intramolecular potential of the D2O solvent. A more accurate intramolecular potential is used for HOD. Our results for the OH stretch, OD stretch, and HOD bend vibrational relaxation times are 2.7, 0.9, and 0.57 ps, respectively. Exciting the OH stretching mode the main relaxation pathway involves a transition to the bending vibration. These results are in agreement with recent semiclassical Landau-Teller calculations. Contrary to this previous work, however, we observe a strong coupling of bending and OH stretching mode to the HOD rotation. As a result almost half of the total vibrational energy is transferred through the HOD rotation to the bath. At the same time the most efficient acceptor mode is the D2O rotation indicating the importance of resonant libration-to-libration energy transfer. We also find significant vibrational excitation of the D2O bending mode of the D2O solvent by V-V energy transfer from the HOD bending mode.