POTENTIAL FUNCTION FOR TELLURIUM HEXAFLUORIDE MOLECULES IN THE SOLID

How accurately various model intermolecular interaction functions are able to reproduce the detailed structure of orthorhombic TeF6 has been investigated by molecular packing analyses. Experimental structure pa rameters were extrapolated to the vibrationless limit. Model potential functions were six- and seven-site pairwise additive atom-atom functi ons including partial charges. Lennard-Jones and Buckingham functions worked equally well. Scoles combining rules gave more consistent resul ts than the conventional Lorenz-Berthelot and Good-Hope rules, Partial charges of approximately 0.21 e(-) on fluorine atoms gave the most ac curate account of the experimental structure parameters. Potential fun ctions based solely on interactions between fluorine sites were distin ctly inferior to functions explicitly incorporating tellurium atoms, A lthough not required to do so by physical principles, the optimal part ial charges for intermolecular interactions agreed well with charges d erived for individual molecules by the Rappe-Goddard charge equilibrat ion method.