On the triple-dipole dispersion energy for non-spherical molecules with an application to the O2O2O2 interaction Original Research Article

The symbolic computation language MAPLE is used to verify an exact expression for the tripple-dipole dispersion energy (DDD), derived previously, for interactions involving up to three linear (∑-state) molecules. The derivation of the original expression, which is complicated, was carried out manually and involved many tedious algebraic steps. Recent results for the anisotropic triple-dipole dispersion energy coefficients for the O2O2O2 interaction, together with the exact expression for the DDD itself, are used to illustrate the importance of the anisotropic dispersion energy, relative to the isotropic triple-dipole energy, and to help investigate the validity of a frequently used average energy approximation for the anisotropic DDD. The discussion includes comments concerning the importance of the DDD energy in the context of the contribution of non-additive energies to the properties of matter.