ANISOTROPY OF LONG-RANGE INTERACTIONS BETWEEN LINEAR-MOLECULES - H2-H2 AND H2-HE

We derive a closed expression for the orientation dependence of the long range interaction coefficients of Ʃ state linear molecules and then calculate the dispersion and induction multipole interaction coefficients for the systems H2-H2 and H2-He up to R-10 terms inclusive. The monomer states are described by SCF-LCAO wave functions with polarization functions optimized with respect to the different multipole polarizabilities. The anisotropy factors ϒ8 and ϒ10, describing the orientation dependence of the R-8 and R-10 terms, are approximately equal and much larger than ϒ6, due to the occurrence of the (completely anisotropic) mixed-pole terms. © Taylor & Francis Group, LLC.