Orbital Optimization in the Active Space Decomposition Model

Inkoo Kim, Shane M. Parker, Toru Shiozaki*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)3636-3642
Number of pages7
JournalJournal of Chemical Theory and Computation
Issue number8
StatePublished - Aug 11 2015

ASJC Scopus subject areas

  • Computer Science Applications
  • Physical and Theoretical Chemistry


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