Shock compression of preheated molybdenum to 300 GPa

Shock compression experiments on samples at elevated initial temperature provide a test of the Mie-Grüneisen method of predicting off-principal Hugoniot states. Pure molybdenum, preheated to 1673 K, was shocked to peak pressures up to 300 GPa, double the compression range previously studied for this material at elevated temperature. The data lie strictly below the cold Hugoniot of Mo in shock velocity vs. particle velocity space, with some downward curvature. Previous approximations and extrapolations from lower-compression data fail to match these results, but the data are well fit by a Mie-Grüneisen correction to the cold Hugoniot. However, the data are insufficiently precise and the phases obtained in the shock experiments too uncertain to discriminate among different functional forms of the density dependence of the Grüneisen parameter.