X-ray diffraction studies on the structure of water at high temperatures and pressures
作者:
Tamás Radnai,
Hitoshi Ohtaki,
期刊:
Molecular Physics
(Taylor Available online 1996)
卷期:
Volume 87,
issue 1
页码: 103-121
ISSN:0026-8976
年代: 1996
DOI:10.1080/00268979600100041
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
X-Ray diffraction measurements of liquid water at high temperatures and pressures (up to 200 °C and 200 MPa) are reported. A diffractometer with a transmission geometry and a cylindrical sample holder made of beryllium were used, with a specially designed high pressure unit. The data reduction procedures are described in detail. The analysis of the structure functions and radial distribution functions show that the O-O distances shorten due to pressure but they are elongated with increasing temperature. The average contraction rate is 0·02 pm MPa-1. The average coordination number of the first neighbour molecules does not change significantly with increasing temperature but slightly increases with increasing pressure. The density dependence of the distances and coordination are discussed. The expansion of water is proportional to the expansion of first neighbour distances in the medium density region only (0·95-1·01 g cm-3), while the coordination number produces a minimum in the medium density region. This is an indication of coexistence of unchanged H bonds with deformed or disrupted H bonds in the pressure and temperature region studied.
点击下载:
PDF (1076KB)
返 回