Binding-energy relations and equations of state for the 4d and 5d transition metals

A recently proposed six-parameter mixed power-exponential expression is tested against density-functional theory binding-energy curves and equations of state across the 4d and 5d transition-metal series. It is shown to remove known failures of the popular Birch-Murnaghan, extended Rydberg, and generalized Morse expressions in that it is able to not only reproduce the observed hard-core repulsion of the early transition metals under compression but also remove predicted spurious oscillations in the binding-energy relations under expansion. However, it is unable to fit the well-known anomalous behavior of the equation of state for lanthanum.