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Title: High-temperature high-pressure Raman spectra from liquid water

Journal Article · · J. Phys. Chem.; (United States)
DOI:https://doi.org/10.1021/j100326a056· OSTI ID:5993453

Raman spectra were obtained from liquid water at 33 kbar and at 170 and 200/degrees/C with a diamond anvil cell. Pressure were determined from the observed ice VII-water melting temperatures. Comparison of the present data, with data from Lindner and Franck, indicates that the OH-stretching peak position, ..delta../anti/v in reciprocal centimeters, decreases with increasing pressure at constant temperature. The OH-stretching peak position, at 33 kbar and 170/degrees/C (Hugoniot conditions), was plotted with Raman data obtained from shock-compressed water. This plot shows a rise in the OH-stretching peak position from about 3410 cm/sup /minus/1/ at 1 atm, to a maximum of about 3440 cm/sup /minus/1/ at about 90 kbar, followed by a decrease to about 3400 cm/sup /minus/1/ at 257 kbar. This maximum is thought to result from two competing effects: (1) hydrogen-bond rupture due to rising temperature and (2) decreasing nearest neighbor O-O distance due to compression, with a concomitant increase of the OH bond length and decrease in the OH-stretching force constant. Further analysis of the data suggests that the double-to-single, hydrogen-bond, potential-well transformation, which is known to occur for linear hydrogen bonds, also occurs for severely bent, non-hydrogen-bonded, O-H-O configurations.

Research Organization:
Howard Univ., Washington, DC (USA)
OSTI ID:
5993453
Journal Information:
J. Phys. Chem.; (United States), Vol. 92:15
Country of Publication:
United States
Language:
English