In:
The Journal of Chemical Physics, AIP Publishing, Vol. 120, No. 5 ( 2004-02-01), p. 2359-2367
Abstract:
We investigate the exciton migration dynamics in a dendritic molecular model composed of π-conjugation linear-leg units (acetylenes and diacetylene) and a benzene ring (branching point) using the quantum master equation approach with the ab initio molecular orbital (MO) configuration interaction (CI) method. The efficient migration of exciton from short-length linear legs (acetylenes) to long-length linear leg (diacetylene) via a benzene ring is observed. As predicted in previous studies, the exciton (electron and hole) distributions are relatively well localized in each generation segmented by the meta-branching point (meta-substituted benzene ring) though the electron and hole distributions are delocalized and are somewhat spatially different from each other within each generation. It is found that the excitons localized in the generation composed of short linear legs occupy in higher-lying exciton states, while those in the generation composed of long linear legs do in lower-lying ones. These features suggest the decoupling of π-conjugation at the meta-branching point. On the other hand, the relaxation effect between exciton states is found to be caused by the exciton–phonon coupling, in which the existence of common configurations (electron-hole pairs) in CI wave functions between adjacent exciton states (having primary distributions on short and long linear-leg regions, respectively) is important for the relaxation between their exciton states. This feature indicates the importance of partial penetration of π-conjugation through the meta-substituted benzene ring in excited states for such exciton migration.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
2004
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
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