Approximate formulae for calculation of the integral ∫0T Tm exp(-E/RT)dT

In this paper two approximate formulae have been developed for calculation of the integral integral(o)T(m) exp(-E / RT)dT by using integration-by-parts approaches. They are in the following forms: I(m, T) = RTm+2/E+(m+2)RT exp(- T/RT) I(m, T) = RTm+2/E+(m+2(0.00099441E+0.93695599RT) exp(-E/RT) The validity of the two formulae has been confirmed and their accuracies have been tested with data from numerical calculating. In contrast to existing other integral methods, both the present approaches are simply used, accurate, and can be used for arbitrary values of m.