First-principles molecular dynamics studies of liquid selenium close to the critical point

First-principles molecular dynamics simulations of liquid selenium for three different densities at the temperatures 1770 and 1870 K are presented. Whereas the densities for 1770 K have been chosen to correspond to pressures at which recent x-ray diffraction experiments were performed, the densities for 1870 K are related to pressures close to the critical point in the p-T phase diagram. For the lower temperature, close agreement with the most recent x-ray data is found in structure factors and pair distribution functions. For the higher temperature, the structure factors get large at low wavelengths close to the critical point. This indicates a highly compressible liquid as would be expected within the critical regime.