Calculation of the volume effect at an electron phase transition in pure cerium and praseodymium

The experimental values of the volume effect at an electronic phase transition in several rare-earth metals are discussed. Specifically, volume changes at phase transitions in cerium and praseodymium are calculated using a semiphenomenological relationship derived in terms of the Falikov-Ramirez-Kimball model. A number of factors influencing the amount of the volume effect at electronic phase transitions are analyzed.