Intermolecular potential energy function, second virial coefficients, and oligomer properties of hydrogen fluoride

Six recently reported intermolecular potential energy functions for HF–HF interactions are examined and used to calculate classical second virial coefficient curves. Order of magnitude differences exist among the six B(T) curves and none of them decreases with temperature as rapidly as an experimental curve determined in the 19.5–56 °C range. The HF3 potential of Klein, McDonald, and O’Shea appears to give the best overall description of HF–HF interactions and this function is used to calculate properties of several higher (HF)q oligomers. The resulting low energy conformations are cyclic, and the hexamer has a puckered, nonrigid structure. The calculated hydrogen bond energies, F⋅⋅⋅F distances, and the puckered, nonrigid hexamer structure all agree well with the available experimental information.