Three equations of state and their application to transition metals

A modified generalized Morse (mGMSE) equation of state (EOS) is proposed that can incorporate the cohesive energy data correctly. It is compared with a four-parameter modified Rose (MR) EOS, which is proposed by following Rose's approach, and the Murnaghan (MNH) EOS. The MR, mGMSE and MNH EOSs are applied to five transition metals and then compared to the available experimental compression data. The results obtained show that for all pressure ranges, the mGMSE EOS fits experimental data most accurately. From a comparison of the variation in pressure and energy versus the compression ratio between MR and mGMSE EOSs, it is clear that the pressure and energy of the MR EOS oscillate both in the neighborhood of (V/V-0) approximate to 0.005 and in the range (V/V-0) > 1. Generally speaking, the mGMSE EOS has many evident advantages over the other two EOSs, while the practical applications of the MR EOS are seriously limited because of physically incorrect oscillations.