An improved method of calculation of the isotope equilibrium fractionation factors over extended temperature range

On the basis of limited spectroscopic data on molecular vibrations supplemented with mass-spectrometric determination of the isotope fractionation over a limited temperature range a semi-empirical formula was derived, which can be safely used over extended temperature range. The formula proposed for the β-factors is the product of a well known harmonic approximation of the reduced partition function ratio and a relatively less significant correction term. Numerical examples and computer program are given to encourage researchers to use the interpolation formula proposed here in their own investigations. (author). 30 refs, 2 figs, 4 tabs