Probing hydrogen bond strength in liquid water by resonant inelastic X-ray scattering

• The potential energy surface is widely used powerful concept in chemical physics. However, direct experimental access to the local potential energy surface in liquid especially in systems  with strong hydrogen bonds is lacking. We develop general technique demonstrated  for liquid water how to reconstruct from state-of-the-art  sub-natural linewidth resonant inelastic X-ray scattering (RIXS)  the local distribution of OH potential energy curves,  separately for OH bonds with weak and strong hydrogen bond. By this we are able to look on the local structure by characterising  selectively the strength of the hydrogen bond. We present a detailed analysis of the formation of the vibrationally resolved RIXS of liquids using a classical/quantum formalism  based on a combination of {\it ab initio} molecular dynamics, density functional theory calculations and quantum nuclear wave packet propagation. Theory nicely explains shortening of the vibrational progression in liquid phase in comparison with RIXS of free water molecules seen in the experiment by fluctuation of the hydrogen bond  network and coherent excitation of both OH bonds.

Ämnesord

NATURVETENSKAP  -- Kemi -- Teoretisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Theoretical Chemistry (hsv//eng)

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

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