Figure 5.

Aggregate sound velocities and Poisson's ratio for MgO under high pressures. (a) V_L, V_T, and V_B are the longitudinal, transverse, and bulk sound velocities, respectively. Symbols and solid curves are from this study. The dotted curves are results calculated from fluorescence side-band measurements (14); the dashed curves are theoretical results (37). (b) Pressure dependence of Poisson's ratio for MgO compared with different materials, including San Carlos olivine [(Mg_0.88Fe_0.12)₂SiO₄] (3), β-Mg₂SiO₄ (31), solid molecular hydrogen (30), and ice VII (40). The solid curve is the fitted result for MgO given by ν = 0.18 + 1.3 × 10⁻³P + 6.4 × 10⁻⁶P², where P is based on the new primary pressure scale.