The defects in applying the universal equation of state (UEOS) presented by Vinet et al. to the analysis of the experimental isothermal compression data of solids in high-pressure phases are that the fitting parameters have actually little physical meaning and have been increased from the original two to three. In this paper, assuming the isothermal bulk modulus varies linearly with pressure we derive the UEOS with an arbitrary reference point from the UEOS presented by Vinet et al. that will eliminate the defects mentioned above. The test on the isothermal compression of ten metal halides as well as cerium shows that the UEOS in the form given by the paper describes the isothermal behavior of solids in high-pressure phases very well.

• Received 25 September 1997

DOI:https://doi.org/10.1103/PhysRevB.58.20