Local random phase approximation with projected oscillator orbitals
An approximation to the many-body London dispersion energy in molecular systems is expressed as a functional of the occupied orbitals only. The method is based on the local-RPA theory. The occupied orbitals are localized molecular orbitals, and the virtual space is described by projected oscillator orbitals, i.e., functions obtained by multiplying occupied localized orbitals with solid spherical harmonic polynomials having their origin at the orbital centroids. Since we are interested in the longrange part of the correlation energy, responsible for dispersion forces, the electron repulsion is approximated by its multipolar expansion. This procedure leads to a fully nonempirical long-range correlation energy expression. Molecular dispersion coeffi cients calculated from determinant wave functions obtained by a range-separated hybrid method reproduce experimental values with < 15 % error.
KeywordsRPA Oscillator orbitals London dispersion energy Dispersion coeffi cient Local correlation method
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