A comprehensive P-V-T dataset for bcc-Mo was obtained at pressures up to 31 GPa and temperatures from 300 to 1673 K using MgO and Au pressure calibrants. The thermodynamic analysis of these data was performed using high-temperature Birch-Murnaghan (HTBM) equations of state (EOS), Mie-Grüneisen-Debye (MGD) relation combined with the room-temperature Vinet EOS, and newly proposed Kunc-Einstein (KE) approach. The analysis of room-temperature compression data with the Vinet EOS yields V0 = 31.14 ± 0.02 Å3, KT = 260 ± 1 GPa, and KT′ = 4.21 ± 0.05. The derived thermoelastic parameters for the HTBM include (∂KT/∂T)P = −0.019 ± 0.001 GPa/K and thermal expansion α = a0 + a1T with a0 = 1.55 ( ± 0.05) × 10−5 K−1 and a1 = 0.68 ( ± 0.07) × 10−8 K−2. Fitting to the MGD relation yields γ0 = 2.03 ± 0.02 and q = 0.24 ± 0.02 with the Debye temperature (θ0) fixed at 455-470 K. Two models are proposed for the KE EOS. The model 1 (Mo-1) is the best fit to our P-V-T data, whereas the second model (Mo-2) is derived by including the shock compression and other experimental measurements. Nevertheless, both models provide similar thermoelastic parameters. Parameters used on Mo-1 include two Einstein temperatures ΘE10 = 366 K and ΘE20 = 208 K; Grüneisen parameter at ambient condition γ0 = 1.64 and infinite compression γ∞ = 0.358 with β = 0.323; and additional fitting parameters m = 0.195, e0 = 0.9 × 10−6 K−1, and g = 5.6. Fixed parameters include k = 2 in Kunc EOS, mE1 = mE2 = 1.5 in expression for Einstein temperature, and a0 = 0 (an intrinsic anharmonicity parameter). These parameters are the best representation of the experimental data for Mo and can be used for variety of thermodynamic calculations for Mo and Mo-containing systems including phase diagrams, chemical reactions, and electronic structure.

The pressure-induced shift of Sm:SrB₄O₇ fluorescence was calibrated in a quasi-hydrostatic helium medium up to 60 GPa using the recent Sm-doped yttrium-aluminum garnet primary pressure scale as a reference. The resulting calibration can be written as P = −2836/14.3 [(1 + Δλ/685.51)^−14.3− 1]. Previous calibrations based on the internally inconsistent primary scales are revised, and, after appropriate correction, found to agree with the proposed one. The calibration extended to 120 GPa was also performed using corrected previous data and can be written as P = 4.20 Δλ (1 + 0.020 Δλ)/(1 + 0.036 Δλ).

A comprehensive P-V-T dataset for bcc-tungsten was obtained for pressures up to 33.5 GPa and temperatures 300–1673 K using MgO and Au pressure scales. The thermodynamic analysis of these data was performed using high-temperature (HT) and Mie-Grüneisen-Debye (MGD) relations combined with the Vinet equations of state (EOS) for room-temperature isotherm and the newly proposed Kunc-Einstein (KE) EOS. The KE EOS allowed calibration of W thermodynamic parameters to the pressures of at least 300 GPa and temperatures up to 4000 K with minor uncertainties (<1% in calculated volume of W). A detailed analysis of room-temperature compression data with Vinet EOS yields V₀ = 31.71 ± 0.02 ų, K_T = 308 ± 1 GPa, and K_T′ = 4.20 ± 0.05. Estimated thermoelastic parameters for HT include (∂K_T/∂T)_P = −0.018 ± 0.001 GPa/K and thermal expansion α = a₀ + a₁T with a₀ = 1.35 (±0.04) × 10⁻⁵ K⁻¹ and a₁ = 0.21 (±0.05) × 10⁻⁸ K⁻². Fitting to the MGD relation yielded γ₀ = 1.81 ± 0.02 and q = 0.71 ± 0.02 with the Debye temperature (θ₀,) fixed at 370–405 K. The parameters for KE EOS include two Einstein temperatures, Θ_E1o = 314 K and Θ_E2o = 168 K, Grüneisen parameter at ambient condition γ₀ = 1.67 and infinite compression γ_∞ = 0.66, with β = 1.16 (which is a power-mode parameter in the Grüneisen equation), anharmonicity (m = 3.57) and electronic (g = 0.11) equivalents of the Grüneisen parameter, and additional parameters for intrinsic anharmonicity, a₀ = 6.2 × 10⁻⁵ K⁻¹, and electronic contribution, e₀ = 4.04 × 10⁻⁵ K⁻¹ to the free energy. Fixed parameters include k = 2 in KE EOS and m_E1 = m_E2 = 1.5 in expression for Einstein temperature. Present analysis should represent the best fit of the experimental data for W and can be used for a variety of thermodynamic calculations for W and W-containing systems including phase diagrams, chemical reactions, and electronic structure.