Matrix computation of the statistical mechanics of a lattice model of multistep benzene adsorption isotherms in silicalite

An almost exact calculation of the statistical mechanics of a lattice model of benzene adsorption in the quasi one-dimensional pores of zeolites is presented. Our calculation attributes the experimentally observed steps in the level of adsorption with rising pressure, to re-orientational and positional transitions amongst molecules in the adsorbed phase. The model also satisfactorily reproduces the essential features of the very unusual temperature dependence of the isotherms.