Hydrogen bonding and coordination in normal and supercritical water from X-ray inelastic scattering

Abstract

A direct measure of hydrogen bonding in water under conditions ranging from the normal state to the supercritical regime is derived from the Compton scattering of inelastically-scattered X-rays. First, we show that a measure of the number of electrons $n_e$ involved in hydrogen bonding at varying thermodynamic conditions can be directly obtained from Compton profile differences. Then, we use first-principles simulations to provide a connection between $n_e$ and the number of hydrogen bonds $n_{HB}$. Our study shows that over the broad range studied the relationship between $n_e$ and $n_{HB}$ is linear, allowing for a direct experimental measure of bonding and coordination in water. In particular, the transition to supercritical state is characterized by a sharp increase in the number of water monomers, but also displays a significant number of residual dimers and trimers.

arXiv comment14 pages, 5 figures, 1 table

References in corpus (6)

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• On electrons and hydrogen-bond connectivity in liquid water
• A first principles simulation of rigid water
• Ab initio calculations of the hydrogen bond
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Cited by in corpus (8)

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• Temperature dependence of the hydrogen bond network in Trimethylamine N-oxide and guanidine hydrochloride - water solutions
• Enhancement of Compton Scattering by an Effective Coupling Constant
• Molecular mean field theory for liquid water