Effect of the breakdown of the rule of the geometric mean on fractionation factor theory

Abstract

The rule of the geometric mean ⁴ does not hold for H₂O + D₂O mixtures. Correction functions to the usual equations of fractionation factor theory have been calculated for two site and three site molecules when isotopic substitution of the various sites is not independent. The significance of the correction functions is discussed and in many cases they are shown to be negligible providing that a value of ϕ measured about or close to n=½ is used.