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Nearest-neighbor oxygen distances in liquid water and ice observed by x-ray Raman based extended x-ray absorption fine structure

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/1.2784123· OSTI ID:21024455
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  1. Stanford Synchrotron Radiation Laboratory, P.O. Box 20450 Stanford, California 94309 (United States)
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 deg. 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 A ring for water and 2.76 A ring for ice) but a slightly shorter peak position (2.70 A ring for water and 2.71 A ring 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.
OSTI ID:
21024455
Journal Information:
Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 17 Vol. 127; ISSN JCPSA6; ISSN 0021-9606
Country of Publication:
United States
Language:
English