Lattice Theories of the Liquid State

Abstract

The assumptions underlying the lattice theory of liquids of Lennard‐Jones and Devonshire are examined. Four modifications of this theory have been proposed which avoid some of these assumptions. These modifications are (a) by Cernuschi and Eyring, (b) by Ono, (c) by Peek and Hill, and (d) one suggested in this paper. It is shown that they may all be deduced as special cases of one mathematical treatment. They are intuitively more attractive than the original theory and avoid any mention of the so‐called ``communal entropy.'' They give reasonable values of the second virial coefficient. None of them, though, shows much improvement over the original theory in calculating the critical constants and vapor pressure curves.