In this work, we implement a series of linear response coupled cluster methods for computing higher-order multipole polarizabilities (e.g., quadrupole, octupole, dipole-quadrupole, etc.) which include up to quadruple excitations (LR-CCSD, LR-CCSDT, and LR-CCSDTQ) in the NWCHEM quantum chemistry program. As an initial application, we constructed two datasets, Atoms-Ions-Multipole-Polarizabilities-20 (AIMP20, which includes 20 atoms and ions) and Molecules-Multipole-Polarizabilities-11 (MMP11, which includes 11 small molecules), which provide benchmark LR-CC results for dipole, quadrupole, and octupole polarizabilities at the complete basis set limit. These datasets have been utilized to assess a wide range of theoretical methods, in which we find that second-order Møller-Plesset (MP2) perturbation theory and the SCAN0 hybrid density functional yield the most accurate descriptions of atomic, ionic, and molecular multipole polarizabilities. Furthermore, the three best basis sets for computing multipole polarizabilities are LPolX-fs, d-aug-pc-2, and aug-pc-3, which are significantly reduced in size when compared to the traditional series of multiply augmented Dunning-style correlation-consistent basis sets and can therefore be used to compute accurate and reliable multipole polarizabilities in larger molecular systems. Employing our best LR-CC static multipole polarizabilities as input into the hollow-sphere model for generating dynamic (frequency-dependent) multipole polarizabilities, we computed C6, C8, and C10 dispersion coefficients with remarkable accuracy for 15 atom-atom, 55 atom-molecule, and 66 molecule-molecule pairs. The robustness of this model, when used in conjunction with accurate static multipole polarizabilities as input, provides a universal method for effectively generating C6, C8, and C10 dispersion coefficients. This advance will allow us to critically assess how important these higher-order dispersion contributions are in determining the structure and stabilities of a number of important systems, including complex polarizable nanostructures, supramolecular/host-guest complexes, and polymorphs of molecular crystals across a wide range of thermodynamic (p-T) conditions.

Multipole polarizabilities at the linear response coupled cluster level

256th National Meeting (2018)

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