Molecular orientational correlation in liquid halogens

Abstract

The characteristic features of structure factor Sm(Q) of liquid halogens F2, Cl2, Br2, and I2 have been discussed in terms of preferred orientational correlations introduced between the nearest neighbors. The orientational correlations estimated directly from the experimental Sm(Q)’s of these liquids are rather similar to each other and are related to a ‘‘staggered parallel’’ orientation proposed previously for liquid Br2. The characteristic features of these Sm(Q)’s are interpreted quite well by two structurally simple quantities, i.e., the ratio of intramolecular bond length to intermolecular center–center separation of correlated molecules l/Rc and that of intramolecular bond length to effective diameter of uncorrelated molecule l/σ. The characteristic features of the experimental radial distribution functions are also reproduced quite well.