An intermolecular potential for (NH3)2

Abstract

Model interatomic potential energy functions are presented for the ammonia dimer (NH3)2 which have the correct Coulombic and dispersion interactions for asymptotically large intermolecular separations. Existing data for the second virial coefficient of the gas together with the known structure and binding energy of the solid are used to constrain the parameters of the short range interatomic interactions. Finally, new experimental results for the differential collision cross section of NH3+NH3 are used to test the proposed potential energy functions.