Statistical Mechanics of Monatomic Systems in an External Periodic Potential Field. I. Introduction, Virial Expansion, and Classical Second Virial Coefficient

Abstract

In the first section a general research program is outlined which is concerned with the behavior of an equilibrium macroscopic system (gas, liquid, or solid) of monatomic molecules in an external periodic potential field. The problems of particular interest are: condensation theory; crystalline state and theory of fusion; ideal degenerate gases; distribution functions; virial expansion for a gas; and the very dilute gas. In the second section the virial expansion is discussed and the classical second virial coefficient for an adsorbed monolayer on a crystal surface is calculated as an illustration. This computation is compared with results obtained from the two conventional cases which are limiting forms of the present treatment: mobile and localized adsorption. The differences are considerable.