Numerical calculations of optical lineshapes for disordered molecular aggregates

Makhov, Dmitry V.; Егоров, Владимир В.; Bagatur’yants, A. A.; Алфимов, М. В.

doi:10.1016/0009-2614(95)01130-4

Cited by 36 publications

(19 citation statements)

References 6 publications

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“…Using this transformation, the average over ′ 1 may indeed be carried out explicitly. To this end, consider the special case 28 of the average eq 10 with f(ω -…”

Section: Hamiltonian Diagonalization and Smoothingmentioning

confidence: 99%

Pump−Probe Spectroscopy and the Exciton Delocalization Length in Molecular Aggregates

Bakalis¹,

Knoester²

1999

J. Phys. Chem. B

106

131

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Using numerical simulations, we investigate to what extent the pump-probe spectrum can be used as a tool to determine the exciton delocalization length in disordered molecular (J) aggregates. We compare the delocalization length obtained through heuristic arguments from the spectral separation between the bleaching and the one-to two-exciton induced absorption features in this spectrum to the delocalization length obtained from the participation ratio at the J band center. We find that up to a certain saturation length these two delocalization lengths are indeed proportional. In the case of long-pulse two-color pump-probe spectra, the slope of this linear scaling is insensitive to the pump frequency; it is sensitive to the width of the probe pulse. Beyond the saturation length, which is determined by the homogeneous line width of the exciton transitions, both the two-color and the short-pulse pump-probe spectra saturate and no longer can be used as a measure for the delocalization length. The latter applies to the B850 ring of bacterial antenna complexes.

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“…Using this transformation, the average over ′ 1 may indeed be carried out explicitly. To this end, consider the special case 28 of the average eq 10 with f(ω -…”

Section: Hamiltonian Diagonalization and Smoothingmentioning

confidence: 99%

Pump−Probe Spectroscopy and the Exciton Delocalization Length in Molecular Aggregates

Bakalis¹,

Knoester²

1999

J. Phys. Chem. B

106

131

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show abstract

“…15,33 One of the important effects of disorder is that it leads to localization of the optically active states near the band edges. In the current model disorder can be viewed as yet another source for exciton scattering, causing the initial exciton population to be redistributed over the lowest few states.…”

Section: B Diagonal Static Disordermentioning

confidence: 99%

Exciton superradiance in aggregates: The effect of disorder, higher order exciton-phonon coupling and dimensionality

Potma

Wiersma

1998

The Journal of Chemical Physics

137

129

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In this paper a detailed theoretical analysis is presented of the temperature dependent radiative decay in aggregates of pseudoisocyanine ͑PIC͒. Our approach extends the original linear exciton-phonon coupling model used by Spano, Kuklinsky, and Mukamel ͓Phys. Rev. Lett. 65, 212 ͑1990͔͒ including static disorder and second order exciton-phonon interactions. It is shown that for a one-dimensional exciton model neither of these additional effects alone or in combination with linear electron-phonon coupling can explain the steep rise in radiative lifetime at 40 K observed in the J-aggregate of PIC. However, when the aggregate assembles into a two-dimensional bricklike structure its radiative dynamics can be simulated, with linear exciton-optical phonon coupling as the only source for exciton scattering. Exciton-phonon scattering transfers oscillator strength from the kϭ0 state to other band states and also generates a nonequilibrium population among the exciton states, which persists during the superradiant decay. These effects together explain the marked temperature dependence of the radiative lifetime of the PIC J aggregate. When disorder limits the coherence length at low temperatures to a few molecules, as seems the case in several light harvesting complexes, the exciton population can equilibrate on the time scale of the superradiance. This situation pertains to the strong collision limit of the master equation, where the radiative decay is insensitive to details of the electron-phonon coupling, but only senses change in the thermal population among the exciton states.

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“…(1) for 10 3 disorder realizations and using the procedure of Ref. [36] to minimize numerical noise in the spectra. In all calculations, we considered cylinders of N ¼ 6000 molecules.…”

Section: Signature Of Anomalous Exciton Localization In the Optical Rmentioning

confidence: 99%

Signature of Anomalous Exciton Localization in the Optical Response of Self-Assembled Organic Nanotubes

et al. 2015

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Signature of Anomalous Exciton Localization in the Optical Response of Self-Assembled Organic Nanotubes Bloemsma, E. A.; Vlaming, S. M.; Malyshev, V. A.; Knoester, J. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. We show that the disorder scaling of the low-temperature optical absorption linewidth of tubular molecular assemblies sharply contrasts with that known for one-dimensional aggregates. The difference can be explained by an anomalous localization of excitons, which arises from the combination of longrange intermolecular interactions and the tube's higher-dimensional geometry. As a result, the exciton density of states near the band bottom drops to zero, leading to a strong suppression of exciton localization. Our results explain the strong linear dichroism and weak exciton-exciton scattering in tubular J aggregates observed in experiments and suggest that for nanoscale wirelike applications a tubular shape is to be preferred over a truly one-dimensional chain.

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Numerical calculations of optical lineshapes for disordered molecular aggregates

Cited by 36 publications

References 6 publications

Pump−Probe Spectroscopy and the Exciton Delocalization Length in Molecular Aggregates

Pump−Probe Spectroscopy and the Exciton Delocalization Length in Molecular Aggregates

Exciton superradiance in aggregates: The effect of disorder, higher order exciton-phonon coupling and dimensionality

Signature of Anomalous Exciton Localization in the Optical Response of Self-Assembled Organic Nanotubes

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