First-principles study of the high-pressure hexagonal-close-packed phase of mercury

A recent experiment by Takemura et al ( 2005 Proc. Joint 20th AIRAPT-43rd EHPRG (Karlsruhe, June-July)) on the pressure-induced hexagonal-close-packed phase of mercury, at pressures between 0.5 and 2 Mbar, has produced reliable data on lattice parameters, axial ratio and the equation of state. We have carried out first-principles calculations at 0 K of the structure parameters as functions of pressure by minimization of the Gibbs free energy. The agreement of the calculated lattice parameters and axial ratio with experiment is in the range of 1% for the lattice parameters and 2% for the axial ratio; the corresponding agreement for the equation of state is between 2 and 3%.