Helmholtz: Cpo(Ideal Gas)
Cpo/R = 1 + t - {åai×ni×(ni - 1)×tni}(ni¹ 0 or 1) + åbi×(ci×t)2×exp(ci×t) / {exp(ci×t) - 1}2;where t = Tc/T, Tc = the critical temperature, and the summations are from i = 1 to nTerms.
The example is for fitted heat capacities in the ideal-gas state at p = 100 kPa for 2-methylpyrrole.