Molecular origin of the difference in the HOH bend of the IR spectra between liquid water and ice
Molecular origin of the difference in the HOH bend of the IR spectra between liquid water and ice
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DOI：
10.1063/1.4789951
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发表时间：
2013-02-07
影响因子：
4.4
通讯作者：
Saito, Shinji
中科院分区：
文献类型：
--
作者：
Imoto, Sho;Xantheas, Sotiris S.;Saito, Shinji
冰的红外光谱中HOH弯曲的强度明显小于液态水中的相应弯曲强度。用柔性的、可极化的、基于从头算的水的TTM3-F模型，用分子动力学(MD)模拟研究了这两个体系中HOH弯曲的IR强度的差异，该势正确地再现了实验观察到的液态水和冰中HOH角从水单体值增加的情况。我们已经确定了导致液态水和冰中HOH弯曲强度不同的两个因素：(I)由于分子的永久偶极矩与相邻氢键受体分子的诱导偶极矩之间的强烈反关联而导致冰中HOH弯曲强度的降低，以及(Ii)由于液态水中无序的氢键网络而减弱了这种反关联。用TTM3-F势从头算计算了水五聚体团簇的电子结构，进一步证实了冰中反关联的存在。(C)2013年美国物理研究所。[http://dx.doi.org/10.1063/1.4789951]
The intensity of the HOH bend in the infrared (IR) spectrum of ice is significantly smaller than the corresponding one in liquid water. This difference in the IR intensities of the HOH bend in the two systems is investigated using Molecular Dynamics (MD) simulations with the flexible, polarizable, ab initio based TTM3-F model for water, a potential that correctly reproduces the experimentally observed increase of the HOH angle in liquid water and ice from the water monomer value. We have identified two factors that are responsible for the difference in the intensity of the HOH bend in liquid water and ice: (i) the decrease of the intensity of the HOH bend in ice caused by the strong anti-correlation between the permanent dipole moment of a molecule and the induced dipole moment of neighboring hydrogen bond acceptor molecules, and (ii) the weakening of this anti-correlation by the disordered hydrogen bond network in liquid water. The presence of the anti-correlation in ice is further confirmed by ab initio electronic structure calculations of water pentamer clusters extracted from the trajectories of the MD simulations with the TTM3-F potential for ice and liquid water. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4789951]