Nearest-neighbor oxygen distances in liquid water and ice observed by x-ray Raman based extended x-ray absorption fine structure
Nearest-neighbor oxygen distances in liquid water and ice observed by x-ray Raman based extended x-ray absorption fine structure
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DOI：
10.1063/1.2784123
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发表时间：
2007-11-07
影响因子：
4.4
通讯作者：
Nilsson, Anders
中科院分区：
文献类型：
--
作者：
Bergmann, Uwe;Di Cicco, Andrea;Nilsson, Anders
本文报道了用基于x射线拉曼的扩展x射线吸收精细结构（EXAFS）光谱获得的室温液态水和多晶冰Ih（-16.8℃）的最近邻氧-氧径向分布函数（NN O-O RDF）。在相同的实验条件下，用相同的方法对两种体系进行了光谱分析，得到了NN - O-O的RDFs。该方案保证了相对距离分布的测量与非常小的系统误差。发现水的NN O-O RDF更不对称（尾部延伸到更长的距离），平均距离更长（水为2.81埃，冰为2.76埃），但峰值位置略短（水为2.70埃，冰为2.71埃）。线性O-H-O多重散射信号对精度的贡献虽小，但意义重大。EXAFS探测器对近距离的高灵敏度将进一步限制液态水可能模型的范围。(c) 2007年美国物理学会。
We report the nearest-neighbor oxygen-oxygen radial distribution function (NN O-O RDF) of room temperature liquid water and polycrystalline ice Ih (-16.8 degrees C) obtained by x-ray Raman based extended x-ray absorption fine structure (EXAFS) spectroscopy. The spectra of the two systems were taken under identical experimental conditions using the same procedures to obtain the NN O-O RDFs. This protocol ensured a measurement of the relative distance distribution with very small systematic errors. The NN O-O RDF of water is found to be more asymmetric (tail extending to longer distances) with longer average distance (2.81 angstrom for water and 2.76 angstrom for ice) but a slightly shorter peak position (2.70 angstrom for water and 2.71 angstrom for ice). The refinement also showed a small but significant contribution from the linear O-H-O multiple scattering signal. The high sensitivity to short range distances of the EXAFS probe will set further restrictions to the range of possible models of liquid water. (c) 2007 American Institute of Physics.