  We report ab initio calculations of the melting curve and Hugoniot of
molybdenum for the pressure range 0-400 GPa, using density functional theory
(DFT) in the projector augmented wave (PAW) implementation. We use the
``reference coexistence'' technique to overcome uncertainties inherent in
earlier DFT calculations of the melting curve of Mo. Our calculated melting
curve agrees well with experiment at ambient pressure and is consistent with
shock data at high pressure, but does not agree with the high pressure melting
curve from static compression experiments. Our calculated P(V) and T(P)
Hugoniot relations agree well with shock measurements. We use calculations of
phonon dispersion relations as a function of pressure to eliminate some
possible interpretations of the solid-solid phase transition observed in shock
experiments on Mo.
