TY  - JOUR
A1  - Niskanen, Johannes
A1  - Fondell, Mattis
A1  - Sahle, Christoph J.
A1  - Eckert, Sebastian
A1  - Jay, Raphael Martin
A1  - Gilmore, Keith
A1  - Pietzsch, Annette
A1  - Dantz, Marcus
A1  - Lu, Xingye
A1  - McNally, Daniel E.
A1  - Schmitt, Thorsten
A1  - Vaz da Cruz, Vinicius
A1  - Kimberg, Victor
A1  - Föhlisch, Alexander
A1  - Gel’mukhanov, Faris
T1  - Compatibility of quantitative X-ray spectroscopy with continuous distribution models of water at ambient conditions
JF  - Proceedings of the National Academy of Sciences of the United States of America
N2  - The phase diagram of water harbors controversial views on underlying structural properties of its constituting molecular moieties, its fluctuating hydrogen-bonding network, as well as pair-correlation functions. In this work, long energy-range detection of the X-ray absorption allows us to unambiguously calibrate the spectra for water gas, liquid, and ice by the experimental atomic ionization cross-section. In liquid water, we extract the mean value of 1.74 +/- 2.1% donated and accepted hydrogen bonds per molecule, pointing to a continuous-distribution model. In addition, resonant inelastic X-ray scattering with unprecedented energy resolution also supports continuous distribution of molecular neighborhoods within liquid water, as do X-ray emission spectra once the femtosecond scattering duration and proton dynamics in resonant X-ray-matter interaction are taken into account. Thus, X-ray spectra of liquid water in ambient conditions can be understood without a two-structure model, whereas the occurrence of nanoscale-length correlations within the continuous distribution remains open.
KW  - structure of water
KW  - X-ray spectroscopy
KW  - continuous distribution model
Y1  - 2019
U6  - https://doi.org/10.1073/pnas.1815701116
SN  - 0027-8424
VL  - 116
IS  - 10
SP  - 4058
EP  - 4063
PB  - National Acad. of Sciences
CY  - Washington
ER  -