Abstract: In this paper, the Martin-Hou equation of state is derived by using a power series representation of radial distribution function and an analytic representation of multi-section potential based on the Barker-Henderson hard-particle perturbation theory including high-order terms.In the derivation, a theoretical form of Martin-Hou equation was obtained.It had a similar form and the same capability to predict P-V-T properties as the Martin-Hou equation and no additional data were required for evaluating the constants.The characteristic constants of the theoretical expression have certain relationships with the molecular parameters.

Key words: Perturbation theory, Martin-Hou equation of state, Theoretical expression, P-V-T properties, Molecular parameter