Hydroxide Hydrogen Bonding: Probing the Solvation Structure through Ultrafast Time Domain Raman Spectroscopy.
Hydroxide Hydrogen Bonding: Probing the Solvation Structure through Ultrafast Time Domain Raman Spectroscopy.
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DOI：
10.1021/jz200350q
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发表时间：
2011-04
期刊：
影响因子：
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通讯作者：
I. Heisler;K. Mazur;S. Meech
中科院分区：
文献类型：
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作者：
I. Heisler;K. Mazur;S. Meech
在分子、材料和生命科学中，水介质中的电荷传输机制是至关重要的。溶剂化氢氧离子的结构一直是一个有争议的领域。本文采用偏振分辨的超快时间域极化率弛豫来解析氢氧化物溶液的太赫兹频率拉曼光谱。测量揭示了溶剂化氢氧化物的完全对称氢键伸展(Ho(-)···HOH)模式，允许实验测量键力常数。将观测到的偏振拉曼光谱与对Ho(-)(H2O)n团簇进行密度泛函计算得到的拉曼光谱进行了比较。对于n=3或4的团簇，观察到的频率与偏振关系有很好的一致性，特别是对于那些溶剂化的水分子采用平面结构的团簇。对称拉伸的频率随浓度的增加而增加，这与离子强度对氢键或团簇结构的影响是一致的。
The mechanism of charge transport in aqueous media is critical in molecular, materials, and life sciences. The structure of the solvated hydroxide ion has been an area of some controversy. Polarization-resolved ultrafast time domain polarizability relaxation is used here to resolve the terahertz frequency Raman spectrum of hydroxide solutions. The measurements reveal the totally symmetric hydrogen-bond stretching (HO(-)···HOH) mode of the solvated hydroxide, permitting an experimental measurement of the bond force constant. The observed polarized Raman spectra are compared with those obtained from DFT calculations performed on HO(-)(H2O)n clusters. Good agreement between the observed frequency and the polarization dependence is found for the n = 3 or 4 clusters, particularly for those in which the solvating water molecules adopt a planar structure. The frequency of the symmetric stretch increases with concentration, consistent with an effect of ionic strength on either the H-bond or the structure of the cluster.