Static structure and dynamical correlations in high pressure H2S

The structure and dynamics of H2S phase IV is investigated via first-princi ples calculations, The weakness of the hydrogen bonding allows for slow rot ational flipping and large fluctuations of the S atoms around their average positions. The S motion is large and correlated and is responsible for the presence of short S-S bonds that are created and destroyed in a dynamical fashion. Our simulated structure compatible with experimental scattering da ta, differs from the previous static models: dynamical correlations in the S positions are essential for a correct description of H2S phase IV.