Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9575357 | Chemical Physics | 2005 | 13 Pages |
Abstract
The dependence of Î and of the decay constant (β) on the methylene-adjacent benzene dihedral angle (θ), for thermal electron transfer in [CH2-(phenylene)n-CH2]â (n = 1, 2, 3) model systems, is studied. Closed-shell Hartree-Fock (RHF) ab initio, through use of Koopmans theorem (KT), open-shell HF (ROHF) and multiconfigurational SCF (MCSCF) level calculations are performed, with several basis sets. A non-exponential distance dependence of Î2 between the methylene groups for some values of θ is found, due to potential energy crossover for the molecules containing one and two phenylene units and due to a remarkable different dependence of Î2 on θ for n = 3, at MCSCF level. The effects of orbital relaxation and electronic correlation in both Î and are also analyzed. Though Î values depend significantly on θ, β values are fairly dependent on this angle in the ranges 0-70° (at KT level), 0-75° (at ROHF level) and 0-50° (at MCSCF level) and show a sudden increase at â¼85-90°, points at which an exponential behavior is obtained.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Silmar A. do Monte, E. Ventura, A.A.S. da Gama,