Effective Intermolecular Interaction Potentials of Gaseous Fluorine,Chlorine, Bromine,and Iodine

Results are presented for binary intermolecular interactions and thermophysical properties in the temperature range between 70K and 1,000K of gaseous fluorine (F₂), and between 200K and 1,000K of chlorine (Cl₂), bromine (Br₂), and iodine (I₂). Our studies are carried out with an (n − 6) Lennard-Jones temperature-dependent potential (LJTDP). The underlying model takes into account the influence of vibrational excitations on the equilibrium distance R _m(T) and potential well depth e(T){\varepsilon(T)} . The potential parameters at T = 0K have been obtained by minimization of the sum of squared deviations between experimentally determined and calculated second pVT- and acoustic virial coefficients, B and β, and viscosities η, normalized to their relative experimental error a _exp. The majority of the available experimental data are well reproduced within their experimental errors. Tables and fitting formulae for a fast and reliable prediction of the thermophysical properties and potential parameters are also presented.