Laikov, D. N. Intrinsic minimal atomic basis representation of molecular electronic wavefunctions. // International Journal of Quantum Chemistry, n/a. doi: 10.1002/qua.22767
The problem of finding an effective minimal atomic basis that spans the exact occupied wavefunctions of a meanfield theory at a given molecular geometry, which has a number of special properties, is studied and a new general procedure is developed that (1) solves for a raw minimal set of strongly atomcentered functions—products of spherical harmonics and moleculeoptimized radial parts—that approximately span the occupied molecular wavefunctions and minimize the sum of their energies, (2) uses projection operators to get a new set of deformed atomcentered functions that exactly span the occupied space and fall into core and valence subsets, (3) applies a new zerobonddipole orthogonalization scheme to the coreorthogonalized valence subset so that for each twocenter product of these functions the projection of its dipole moment along the line going through the two centers is zero. The resulting effective minimal atomic basis is intrinsic to the molecular problem and does not need a freeatoms input. Some interesting features of the zerobonddipole orthogonalization are showing up in the atomic population analysis of a diverse set of molecules. The new procedure may be useful for the interpretation of electronic structure, for the construction of model Hamiltonians in terms of transferable molecular integrals, and for the definition of active valence space in the treatment of electron correlation.
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Model Hamiltonian; minimal atomic basis; transferable integrals; localized orthogonalization; parametrized electronic structure
