This paper contains results for the permanent multipoles, the multipole polarizabilities and the related anisotropic long range interaction coefficients C5 to C10 (complete) for the nitrogen molecule. The electrostatic, induction and dispersion interaction coefficients have been calculated using ab initio SCF wavefunctions ; better estimates for the dispersion terms have been obtained by an approximate procedure, which uses the accurate (semi-) empirical data available for Co and the dipole polarizability, in combination with the ab initio results. The pure quadrupole-quadrupole anisotropy appears to be substantially modified by the dispersion anisotropy and, to a smaller extent, by the higher multipole electrostatic interactions ; the induction energy can be neglected. The dispersion anisotropy factors ys and )'10, are much larger than Y6, due to the occurrence of the (completely anisotropic) mixed-pole terms. The recently proposed non-empirical Uns61d method yields results which support applications to larger molecules.

Using LCAO-SCF wave functions on the monomers and a non-empirical Uns61d procedure for the second-order properties we have calculated the (2 z) multipole moments (up to l= 6), the (l, l') multipole polarizabilities (up to l+l'=6) and the related long-range coefficients describing the electrostatic, induction and dispersion interactions for the different azabenzene molecules. The agreement with available experimental data is good, in particular for the dipole polarizabilities. The .anisotropy of the long-range interaction potential is dominated by the electrostatic contributions, although the dispersion terms, especially the mixed-pole terms (lr for even n (C8, C10), also contribute significantly; the induction energy is rather small. The 7r contributions to the polarizabilities and the dispersion interactions are found to be larger than earlier estimates. Moreover, it is shown by calculating the dipole polarizabilities of some (aza)naphthalenes and (aza)-anthracenes, that a bond polarizability model can be applied effectively only if the delocalized 7r electrons are considered separately from the ~ electrons.

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Articles you may be interested inCollision-induced dipoles and polarizabilities of pairs of hydrogen molecules: Ab initio calculations and results from spherical tensor analysis AIP Conf. Proc. 1504, 100 (2012); 10.1063/1.4771707 Labelfree exchange perturbation approximation for the collisioninduced dipole of HeH A b i n i t i o calculations of the collisioninduced dipole in He-H2. I. A valence bond approachUsing the SCF-LACAO method we have calculated dipole moments of the He-H2 "supermolecule" for a number· of geometries pertinent for the interpretation of the collision-induced IR spectrum. From the results parametrized expressions for j.L have. been obtained, which are compared with expressions used earlier in experimental analyses. Beside the contributions to j.L from the isotropic overlap and He induction by the H 2 -quadrupole, we have found that also the interference of the latter term with the corresponding short range term is important. The zeroth moments of the spectral densities of the rotation-translation band and the enhanced fundamental band have been calculated and are compared with recent experiments.

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