Analytic approximation of the Debye function

Abstract

An expression in a closed form is proposed for the approximation of the Debyefunction used in thermodynamic models of solids. This expression defines an analytic functionthat has the same limiting behavior as the Debye function at low and high temperatures. Theapproximation gives the maximum relative deviation from the value of the Debye function lessthan 0.001. The proposed expression can be useful in the equations of state of solids in a widetemperature range.