Snegirev M. Examination of the critical and overcritical properties of metallic cerium

An investigation of critical point of gamma-alpha phase transition in cerium on the basis of the thermodynamical theory of critical state and Aptecar-Ponytovsky and Rainford-Ewards models is carried out. State and equilibrium line equations, full complex of thermodynamical parameters of models are carried out in analytic form. The behaviour of the full complex of thermodynamic parameters of the system in overcritical area is compared for the models under consideration and known experimental data. The ways to improving models under consideration are analyzed, the full complex of thermodynamic parameters of improved models are obtained and investigated. It was shown that the improved models have the first type or critical behaviour too. The behaviour of the full complex of thermodynamic parameters of improved models in overcritical is compared with the initial models and known experimental data. The behaviour of fluctuations of main thermodynamical variables in the overcritical region is investigated. Onthe basis of the Rainford-Edwards and Aptecar-Ponyatovsky models the Gibbs energy for solid-state cerium and а power series expansion for Gibbs energy of molten cerium an equation of the fusion curve of cerium is established. The values of the melting heat and volume compressibility of cerium are obtained.