Extended dipole model for aggregates of dye molecules

Czikklely, V.; Försterling, Horst‐Dieter; Kuhn, Hans

doi:10.1016/0009-2614(70)80220-2

Cited by 509 publications

(313 citation statements)

References 5 publications

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“…The important point is that the increase in the decay rate was not observed in only the bilayer structure of a type of cyanine molecule; 39 the existence of the different cyanine molecule layer is a key point. When the extended dipole 45 is formed between excitons in the DTTCI and PSA1411 layers in the D-P structure, the exciton lifetime changes with the relationship between the directions of polarization. In particular, the lifetime decreases in the case of parallel direction.…”

Section: -6mentioning

confidence: 99%

Increase in exciton decay rate due to plane-to-plane interaction between cyanine thin films

2016

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Increase in exciton decay rate due to planeto-plane interaction between cyanine thin filmsWe report an increase in exciton decay rates because of long-range interaction based on surface charge between cyanine thin films. The dependence of the decay rate on the spatial separation between the cyanine molecule layers shows that the rate is almost constant, which is different from the well-known energy transfer process. The rate is hardly affected by the fluctuation of the film thickness,

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Section: -6mentioning

confidence: 99%

Increase in exciton decay rate due to plane-to-plane interaction between cyanine thin films

2016

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“…The spectroscopic peculiarities are the result of exceptionally strong electronic interactions between the transition dipole moments of the dyes which give rise to extended exciton states after photo excitation [3,4]. The excitonic absorption spectrum depends on the details of the structural arrangement of the dye molecules within the aggregate [5,6]. A red-shift of the excitonic absorption with respect to the monomer absorption is considered as the characteristic feature of J-aggregates.…”

Section: Introductionmentioning

confidence: 99%

Photo‐induced reduction of Noble metal ions to metal nanoparticles on tubular J‐aggregates

Kirstein

Berlepsch

Böttcher

2006

International Journal of Photoenergy

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Palladium and silver nanoparticles are formed on the surface of tubular J-aggregates of an amphiphilic tetrachlorobenzimidacarbocyanine dye by reduction of the respective metal cations in aqueous solution. Upon addition of the palladium complex Na 2 PdCl 4 to the aggregate solution, the absorption spectrum shows significant changes which is explained by partial destruction of the aggregates. Cryogenic transmission electron microscopy (cryo-TEM) images show that the tubular J-aggregates are randomly covered by well-separated Pd nanoparticles of approximately 1-3 nm size. Larger particles and higher particle density along the aggregates are obtained when an auxiliary reducing agent is added to the solution. The presence of the metallic particles leads to efficient fluorescence quenching giving clear evidence for super quenching. In similar experiments using AgNO 3 , silver nanoparticles are grown which are larger in size but less dense distributed along the aggregates. At least in the case of the silver particles, the spontaneous formation of metal nanoparticles is assumed to be initiated by a photo-induced electron transfer process (PET).

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“…Unlike the Scheibe aggregate situation presented in [59] where the molecules of the monolayer are completely symmetrical around the x-and y-axes, the MT lattice structure does not provide a coordinate system in which the dipole contributions can be separated into two effective coupling constants in distinct directions. Due to the tilted hexagonal structure and the direction of the dipole moment, there is skewed symmetry in the dipole couplings; thus, the second term in (14) may not be written in terms of an orthogonal axis.…”

Section: The Exciton Systemmentioning

confidence: 95%

“…This will also be the approach we take for MTs. A transition dipole moment M is created when an electron makes a transition between its ground and first excited state [59] and may be given in one dimension by:…”

Section: The Exciton Systemmentioning

confidence: 99%

A critical assessment of the information processing capabilities of neuronal microtubules using coherent excitations

Craddock

Tuszyński

2009

J Biol Phys

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Evidence for signaling, communication, and conductivity in microtubules (MTs) has been shown through both direct and indirect means, and theoretical models predict their potential use in both classical and quantum information processing in neurons. The notion of quantum information processing within neurons has been implicated in the phenomena of consciousness, although controversies have arisen in regards to adverse physiological temperature effects on these capabilities. To investigate the possibility of quantum processes in relation to information processing in MTs, a biophysical MT model is used based on the electrostatic interior of the tubulin protein. The interior is taken to constitute a double-well potential structure within which a mobile electron is considered capable of occupying at least two distinct quantum states. These excitonic states together with MT lattice vibrations determine the state space of individual tubulin dimers within the MT lattice. Tubulin dimers are taken as quantum well structures containing an electron that can exist in either its ground state or first excited state. Following previous models involving the mechanisms of exciton energy propagation, we estimate the strength of exciton and phonon interactions and their effect on the formation and dynamics of coherent exciton domains within MTs. Also, estimates of energy and timescales for excitons, phonons, their interactions, and thermal effects are presented. Our conclusions cast doubt on the possibility of sufficiently long-lived coherent exciton/phonon structures existing at physiological temperatures in the absence of thermal isolation mechanisms. These results are discussed in comparison with previous models based on quantum effects in non-polar hydrophobic regions, which have yet to be disproved.

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Extended dipole model for aggregates of dye molecules

Cited by 509 publications

References 5 publications

Increase in exciton decay rate due to plane-to-plane interaction between cyanine thin films

Increase in exciton decay rate due to plane-to-plane interaction between cyanine thin films

Photo‐induced reduction of Noble metal ions to metal nanoparticles on tubular J‐aggregates

A critical assessment of the information processing capabilities of neuronal microtubules using coherent excitations

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