[S-IT19] Deep Earth Sciences

[SIT19-P01] Single crystal elasticity and equation of state of tantalum up to 55 GPa

*Akira Yoneda¹, Hiroshi Fukui², Seiji Kamada³, Hiroshi UCHIYAMA², Naohisa Hirao², Alfred Q.R. Baron² (1.Department of Earth and Space Science, Okayama University, 2.Japan Synchrotron Radiation Research Institute, 3.Frontier Research Institute for Interdisciplinary Sciences)

Keywords:tantalum, inelastic X-ray scattering, diamond anvil cell, single crystal elasticity, primary pressure scale, ruby pressure scale

We measured single crystal elasticity of Ta under high pressure up to ~50 GPa at room temperature using inelastic x-ray scattering at room temperature. Simultaneously we measured the density of Ta using x-ray diffraction. Combining the bulk modulus and density, we obtain an equation of state of Ta as a primary scale. The Vinet equation was fitted to the pressure-volume data and we found consistency with previous work including experimental static and shock compressions and theoretical calculation. We proposed a parameter set for the Vinet equation (K₀=191.1(3) GPa, K’₀=4.006(2)) which is consistent with the primary pressure within 2% up to ~80 GPa. Furthermore, we found the present scale to be consistent with a recent ruby scale (Ruby2020) up to ~50 GPa.