title: Orbital Optimization in the Active Space Decomposition Model.
abstract: We report the derivation and implementation of orbital optimization algorithms for the active space decomposition (ASD) model, which are extensions of complete active space self-consistent field (CASSCF) and its occupation-restricted variants in the conventional multiconfiguration electronic-structure theory. Orbital rotations between active subspaces are included in the optimization, which allows us to unambiguously partition the active space into subspaces, enabling application of ASD to electron and exciton dynamics in covalently linked chromophores. One- and two-particle reduced density matrices, which are required for evaluation of orbital gradient and approximate Hessian elements, are computed from the intermediate tensors in the ASD energy evaluation. Numerical results on 4-(2-naphthylmethyl)-benzaldehyde and [36]cyclophane and model Hamiltonian analyses of triplet energy transfer processes in the Closs systems are presented. Furthermore, model Hamiltonians for hole and electron transfer processes in anti-[2.2](1,4)pentacenophane are studied using an occupation-restricted variant.
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Inkoo
authors.initials: I
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Shane M
authors.initials: SM
authors.lastname: Parker
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Toru
authors.initials: T
authors.lastname: Shiozaki
mesh_terms: D001547:Benzaldehydes / Q000737:chemistry; D004583:Electrons; D004735:Energy Transfer; D008956:Models, Chemical; D011789:Quantum Theory
chemical_list: D001547:Benzaldehydes; C032175:benzaldehyde