Testing isomorph theory on a glass-forming liquid under high pressure using diffraction

The main aim of the proposed experiment is to perform the first experimental test of the prediction from isomorph theory that the structure of a liquid is invariant along the glass-transition line [1]. In addition, we will test a proposed connection between structural changes and changes in dynamics [2]. To achieve this, we will measure the structure factor of a simple molecular glass-forming liquid (cumene) as a function of pressure and temperature, ranging from above the melting point to below the glass transition. [1] Gnan et. al., J. Chem. Phys. 131, 234504 (2009). [2] Phys. Rev. E 94, 060603(R) (2016).