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Enhancement of vibronic and ground-state vibrational coherences in 2D spectra of photosynthetic complexes.

ABSTRACT: A vibronic-exciton model is applied to investigate the recently proposed mechanism of enhancement of coherent oscillations due to mixing of electronic and nuclear degrees of freedom. We study a dimer system to elucidate the role of resonance coupling, site energies, vibrational frequency and energy disorder in the enhancement of vibronic-exciton and ground-state vibrational coherences, and to identify regimes where this enhancement is significant. For a heterodimer representing two coupled bachteriochloropylls of the FMO complex, long-lived vibronic coherences are found to be generated only when the frequency of the mode is in the vicinity of the electronic energy difference. Although the vibronic-exciton coherences exhibit a larger initial amplitude compared to the ground-state vibrational coherences, we conclude that, due to the dephasing of the former, both type of coherences have a similar magnitude at longer population time.

SUBMITTER: Chenu A

PROVIDER: S-EPMC3693153 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Enhancement of vibronic and ground-state vibrational coherences in 2D spectra of photosynthetic complexes.

Chenu Aurélia A Christensson Niklas N Kauffmann Harald F HF Mančal Tomáš T

Scientific reports 20130101

A vibronic-exciton model is applied to investigate the recently proposed mechanism of enhancement of coherent oscillations due to mixing of electronic and nuclear degrees of freedom. We study a dimer system to elucidate the role of resonance coupling, site energies, vibrational frequency and energy disorder in the enhancement of vibronic-exciton and ground-state vibrational coherences, and to identify regimes where this enhancement is significant. For a heterodimer representing two coupled bacht ...[more]

PMID: 23778355

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