{ital Ab} {ital initio} based effective Hamiltonians for long-range electron transfer: Hartree{endash}Fock analysis
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)
An {ital ab} {ital initio} electronic structure method is developed to describe electron transfer in large systems. The method is based on a molecular fragment effective Hamiltonian approach. The strategy pieces together results of {ital ab} {ital initio} quantum chemistry calculations on overlapping molecular segments in order to build an effective Hamiltonian that describes the long-range electronic interactions. This is accomplished by constructing fragment effective Hamiltonians that properly describe the electronic propagation characteristics of each fragment (computed at the {ital ab} {ital initio} Hartree{endash}Fock level in an appropriate basis set). The fragment effective Hamiltonian is projected onto the valence orbital space of each fragment, and a relatively well-localized set of effective interactions is obtained. Combining these projected fragment Hamiltonians allows the construction of a valence effective Hamiltonian for the entire system. We find that the fragment Hamiltonian matrices constructed in this way are transferable between donor{endash}acceptor systems with homologous electron-transfer bridges. The overall strategy of fragmentation and construction of valence effective Hamiltonians could enable {ital ab} {ital initio} quality computations of long-range tunneling interactions in macromolecules. We demonstrate the use of the method in a series of electron-transfer model systems of modest size. {copyright} {ital 1996 American Institute of Physics.}
- DOE Contract Number:
- FG36-94GO10051
- OSTI ID:
- 397442
- Journal Information:
- Journal of Chemical Physics, Vol. 105, Issue 21; Other Information: PBD: Dec 1996
- Country of Publication:
- United States
- Language:
- English
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