On the compatibility of the generalized logarithmic and Rydberg equations of state

It is found that the generalized version of the logarithmic equation of state (EOS) due to Poirier and Tarantola becomes compatible with the generalized Rydberg EOS when we use K ∞ ′ , the value of the pressure derivative of the bulk modulus at infinite pressure equal to 5/3, a result based on the Thomas–Fermi model. The results are obtained for the pressure–volume relationships in case of Fe, Cu and Al up to very high compressions. The results are found to present close agreement with the pressure–volume data for hcp iron obtained by Stacey and Davis by recalibrating the platinum pressure scale used in the laboratory by Mao et al., and also with the values extrapolated from the Stacey EOS.