The structure of water around the compressibility minimum

L B Skinner; C J Benmore; J C Neuefeind; J B Parise

doi:10.1063/1.4902412

The structure of water around the compressibility minimum

J Chem Phys. 2014 Dec 7;141(21):214507. doi: 10.1063/1.4902412.

Authors

L B Skinner¹, C J Benmore¹, J C Neuefeind², J B Parise³

Affiliations

¹ X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
² Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37922, USA.
³ Mineral Physics Institute, Stony Brook University, Stony Brook, New York, New York 11794-2100, USA.

PMID: 25481152
DOI: 10.1063/1.4902412

Abstract

Here we present diffraction data that yield the oxygen-oxygen pair distribution function, g(OO)(r) over the range 254.2-365.9 K. The running O-O coordination number, which represents the integral of the pair distribution function as a function of radial distance, is found to exhibit an isosbestic point at 3.30(5) Å. The probability of finding an oxygen atom surrounding another oxygen at this distance is therefore shown to be independent of temperature and corresponds to an O-O coordination number of 4.3(2). Moreover, the experimental data also show a continuous transition associated with the second peak position in g(OO)(r) concomitant with the compressibility minimum at 319 K.