Ramp compression of tantalum to multiterapascal pressures: Constraints of the thermal equation of state to 2.3 TPa and 5000 K

• Published in: Physical review. B 2023-01, Vol.107 (1), Article 014109
• Main Authors: Gorman, M. G., Wu, C. J., Smith, R. F., Benedict, L. X., Prisbrey, C. J., Schill, W., Bonev, S. A., Long, Z. C., Söderlind, P., Braun, D., Swift, D. C., Briggs, R., Volz, T. J., O'Bannon, E. F., Celliers, P. M., Fratanduono, D. E., Eggert, J. H., Ali, S. J., McNaney, J. M.
• Format: Article
• Language: English
• Subjects: CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Condensed Matter, Materials & Applied Physics; Density functional theory; Equations of state; High-pressure studies; Laser ablation; Polycrystalline materials; Thermal properties; Thermodynamics Metals
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.107.014109

We report measurements of the compressibility of ramp compressed tantalum to a final stress of 2.3 TPa corresponding to threefold volumetric compression. Using these data, we extended the experimental constraint on the Ta cold compression curve by an order of magnitude in pressure. Furthermore, by combining the resulting data with previous measurements of shock compression and ambient pressure heating, we construct an experimentally bounded and thermodynamically consistent equation of state model for Ta which has 2% uncertainty in pressure at 1 TPa. We therefore propose Ta as an in situ pressure scale for laser-heated static compression experiments which were recently able to reach terapascal pressures and thousands of degrees Kelvin. Our new equation of state of Ta is experimentally constrained at extreme pressures and temperatures relevant to a wide range of planetary interiors and will allow for more accurate comparison between experimental measurements and theory at extreme conditions.