Application of Statistical Thermodynamics to the Olfaction Mechanism

The application of the grand canonical ensemble in statisticalthermodynamics to the stimulus adsorption on the olfactory receptorsites, assuming some simplifying hypotheses, leads us to anexpression of the olfactory response R, which is a functionof various physico-chemical parameters involved in the olfactionmechanism, e.g. the stimulus concentration, the saturated vaporpressure, the power law exponent and the partition coefficient.This expression of R is in agreement with the olfactory responseof the Hill model, but is more explicit. Stevens' law and theolfactory threshold expression are easily deduced from R. Theexpression of the threshold we established from R enabled usto explain some empirical relations in the literature betweenthe parameters quoted above. The use of the grand canonicalensemble with the chemical potential notion gave us an interpretationof Stevens' law and a better understanding of the role of someparameters involved in the olfaction mechanism, such as saturatedvapor pressure and power law exponent. Chem. Senses 22: 67–75,1997.