Photonics meets excitonics: natural and artificial molecular aggregates

Saikin, Semion K.; Eisfeld, Alexander; Valleau, Stéphanie; Aspuru‐Guzik, Alán

doi:10.1515/nanoph-2012-0025

Cited by 216 publications

(299 citation statements)

References 182 publications

(209 reference statements)

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“…those deriving from a molecular dynamics simulation [5][6][7][8][9][10][11][12][13] or representing the interaction between chromophores in an amorphous system. [14][15][16][17][18][19][20] To perform these large scale simulations efficiently, to rationalize the observed properties and to design new materials it is important to identify the main components of the excitonic coupling and assess their relative importance.…”

Section: Introductionmentioning

confidence: 99%

Importance and Nature of Short-Range Excitonic Interactions in Light Harvesting Complexes and Organic Semiconductors

Fornari

Rowe

Padula

et al. 2017

J. Chem. Theory Comput.

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Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:"This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Chemical Theory and Computation. copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work http://pubs.acs.org/page/policy/articlesonrequest/index.html ." A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL above for details on accessing the published version and note that access may require a subscription. AbstractThe singlet excitonic coupling between many pairs of chromophores is evaluated in three different Light Harvesting Complexes (LHCs) and two organic semiconductors (amorphous and crystalline). This large database of structures is used to assess the relative importance of short-range (exchange, overlap, orbital) and long-range (Coulombic) excitonic coupling. We find that Mulliken atomic transition charges can introduce systematic errors in the Coulombic coupling and that the dipole-dipole interaction fails to capture the true Coulombic coupling even at intermolecular distances of up to 50 Å. The non-Coulombic short range contribution to the excitonic coupling is found to represent up to ~70% of the total value for molecules in close contact, while, as expected, it is found to be negligible for dimers not in close contact. For the face-to-face dimers considered here, the sign of the short range interaction is found to correlate with the sign of the Coulombic coupling, i.e. reinforcing it when it is already strong. We conclude that for molecules in van der Waals contact the inclusion of short range effects is essential for a quantitative description of the exciton dynamics.

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Section: Introductionmentioning

confidence: 99%

Importance and Nature of Short-Range Excitonic Interactions in Light Harvesting Complexes and Organic Semiconductors

Fornari

Rowe

Padula

et al. 2017

J. Chem. Theory Comput.

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“…However, this process is not unique to photosynthesis. J-aggregates (aka Scheibe aggregates), collections of dye molecules, are an artificial form of LHC capable of capturing and manipulating photon energy [17,18]. At the root, this phenomenon is attributable to the optimal packing of chromophores with a significant transition dipole.…”

Section: Introductionmentioning

confidence: 99%

The feasibility of coherent energy transfer in microtubules

Craddock

Friesen

Mane

et al. 2014

J. R. Soc. Interface.

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It was once purported that biological systems were far too 'warm and wet' to support quantum phenomena mainly owing to thermal effects disrupting quantum coherence. However, recent experimental results and theoretical analyses have shown that thermal energy may assist, rather than disrupt, quantum coherent transport, especially in the 'dry' hydrophobic interiors of biomolecules. Specifically, evidence has been accumulating for the necessary involvement of quantum coherent energy transfer between uniquely arranged chromophores in light harvesting photosynthetic complexes. The 'tubulin' subunit proteins, which comprise microtubules, also possess a distinct architecture of chromophores, namely aromatic amino acids, including tryptophan. The geometry and dipolar properties of these aromatics are similar to those found in photosynthetic units indicating that tubulin may support coherent energy transfer. Tubulin aggregated into microtubule geometric lattices may support such energy transfer, which could be important for biological signalling and communication essential to living processes. Here, we perform a computational investigation of energy transfer between chromophoric amino acids in tubulin via dipole excitations coupled to the surrounding thermal environment. We present the spatial structure and energetic properties of the tryptophan residues in the microtubule constituent protein tubulin. Plausibility arguments for the conditions favouring a quantum mechanism of signal propagation along a microtubule are provided. Overall, we find that coherent energy transfer in tubulin and microtubules is biologically feasible.

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“…(1). Our experimental and theoretical results may provide insight into other systems described by long-range spin models [34][35][36][37][38][39][40][41][42][43][44][45][46][47]-for example, magnetic atoms, Rydberg atoms, trapped ions, and excitons in solid state materials and molecules. In the future it will be fascinating to examine the development of correlations more directly and to explore transport and thermalization, or lack thereof, e.g., glassiness and many-body localization [48][49][50][51].…”

mentioning

confidence: 99%