Journal of Statistical Physics, Vol. 9, No. 4, 1973 Some Properties of the Informational Model of the Liquid State Witold Brostow 1 and Yvon Sicotte 1 Received March 6, 1973; revised June 1, 1973 Equilibrium propertiesof one-component liquids are obtainable--as suggested by Collins--from the coding procedure in terms of distances between neigh- boring molecules. The monatomic case is dealt with first, and consequences of some simplifying assumptions are explored. The connection between the probability r of an intermolecular distance R and the usual pair distribu- tion function is considered. The treatment is then generalized to the case of heterogeneous multiatomic molecules. KEY WORDS: Information theory; liquid state; statistical mechanics; thermodynamic properties. 1. INTRODUCTION Among fundamental approaches to the liquid state, there are two relatively much less exploited than the rest: physical models and the informational method. These two approaches are also the most recent ones, which partly explains their current situation. The method of physical models is frequently associated with the name of Bernal; binary radial distribution function g(R) curves, obtained by Bernal and his colleagues counting distances R between bails, turned out to be comparable m to the results obtained for real liquids such as argon using X-ray and neutron diffraction techniques. Related studies have been made by Scott.(2) As discussed by Pryde, c8~an interesting result of Scott is reproduction by a system of balls of the volume change on melting of monatomic liquids. 1 D6partement de Chimie, Universit6 de Montr6al, Montr6al, P.Q., Canada. 339 9 1973 Plenum Publishing Corporation, 227 West 17th Street, New York, N.Y. 10Ol 1. 822/9/4-.5