  We report a combined experimental and theoretical study of the melting curve
and the structural behavior of vanadium under extreme pressure and temperature.
We performed powder x-ray diffraction experiments up to 120 GPa and 4000 K,
determining the phase boundary of the bcc-to-rhombohedral transition and
melting temperatures at different pressures. Melting temperatures have also
been established from the observation of temperature plateaus during laser
heating, and the results from the density-functional theory calculations.
Results obtained from our experiments and calculations are fully consistent and
lead to an accurate determination of the melting curve of vanadium. These
results are discussed in comparison with previous studies. The melting
temperatures determined in this study are higher than those previously obtained
using the speckle method, but also considerably lower than those obtained from
shock-wave experiments and linear muffin-tin orbital calculations. Finally, a
high-pressure high-temperature equation of state up to 120 GPa and 2800 K has
also been determined.
