Local self-motion of water through the Van Hove function

Area of Science:

• Condensed Matter Physics
• Chemical Physics
• Materials Science

Background:

• The Van Hove function describes particle correlations and dynamics in liquids.
• Understanding local molecular motion is crucial for liquid properties.

Purpose of the Study:

• To experimentally determine the self-part of the Van Hove function for water.
• To investigate short-range molecular dynamics in liquids using a novel approach.

Main Methods:

• High-resolution inelastic X-ray scattering (IXS) experiments were performed.
• IXS spectra were analyzed up to momentum transfer of 10 Å⁻¹.
• The self-part of the Van Hove function was extracted from short-range correlations.

Main Results:

• The self-part of the Van Hove function for water was successfully determined.
• Diffusivity calculated from short-range dynamics differs from long-range measurements.
• Experimental validation of extracting molecular dynamics from IXS.

Conclusions:

• Inelastic X-ray scattering is a powerful tool for probing local molecular dynamics.
• The determined self-part of the Van Hove function provides insights into short-range liquid behavior.
• This method advances the study of atomic and molecular dynamics in liquids.