Intermolecular repulsive–dispersive potentials explain properties of impurity spectra in soft solids

Renge, Indrek; Rätsep, Margus; Freiberg, Arvi

doi:10.1016/j.jlumin.2010.10.008

Cited by 10 publications

(8 citation statements)

References 29 publications

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“…The excitonic lineshapes from all states are then summed to produce the pre-burn absorption spectrum. The calculated line shapes depend in both cases on the temperature (T, set to 5 K in these calculations), electronÀphonon coupling strength S (which, although not considered here, has for some systems 21 been suggested to itself vary with site energy), and the phonon spectral density (or equivalently, the one-phonon profile, in HB terminology 11 ). In the more flexible density matrix theory, the line shape also depends on the pigment site energies and an assumed correlation radius for protein phonon modes (see Supporting Information for further comparison of the present method with the formulas used in previous work).…”

Section: Section: Kinetics Spectroscopymentioning

confidence: 99%

Modeling of Resonant Hole-Burning Spectra in Excitonically Coupled Systems: The Effects of Energy-Transfer Broadening

Reppert

2011

J. Phys. Chem. Lett.

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Section: Section: Kinetics Spectroscopymentioning

confidence: 99%

Modeling of Resonant Hole-Burning Spectra in Excitonically Coupled Systems: The Effects of Energy-Transfer Broadening

Reppert

2011

J. Phys. Chem. Lett.

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“…According to Equation (5), the ΔFLN spectrum displays an origin band that comprises the ZPL and PSB components, with intertwined I vib + I mq vibrational sidebands extending toward longer wavelengths. The shape of the origin band I 00 (ν) is known to depend on the excitation wavelength, with significant variations observed even for small changes within the inhomogeneous spread of ZPL frequencies, showing enhancement of the electron-phonon coupling strength with increasing transition wavelength (Rätsep et al, 2009b ; Renge et al, 2011 ). Comparing the low-resolution spectra obtained in different environments, one may conclude that the vibrational sideband is more intense in 1-propanol than in TEA, details of which are revealed by the ΔFLN spectra.…”

Section: Resultsmentioning

confidence: 99%

Asymmetry in the Qy Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics

2020

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Significant asymmetry found between the high-resolution Qy emission and absorption spectra of chlorophyll-a is herein explained, providing basic information needed to understand photosynthetic exciton transport and photochemical reactions. The Qy spectral asymmetry in chlorophyll has previously been masked by interference in absorption from the nearby Qx transition, but this effect has recently been removed using extensive quantum spectral simulations or else by analytical inversion of absorption and magnetic circular dichroism data, allowing high-resolution absorption information to be accurately determined from fluorescence-excitation spectra. To compliment this, here, we measure and thoroughly analyze the high-resolution differential fluorescence line narrowing spectra of chlorophyll-a in trimethylamine and in 1-propanol. The results show that vibrational frequencies often change little between absorption and emission, yet large changes in line intensities are found, this effect also being strongly solvent dependent. Among other effects, the analysis in terms of four basic patterns of Duschinsky-rotation matrix elements, obtained using CAM-B3LYP calculations, predicts that a chlorophyll-a molecule excited into a specific vibrational level, may, without phase loss or energy relaxation, reemit the light over a spectral bandwidth exceeding 1,000 cm−1 (0.13 eV) to influence exciton-transport dynamics.

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“…The measurements were performed at 4.5 ± 0.2 K in a He bath cryostat (Utreks), as described previously. − Selective excitation of fluorescence was performed using a model 375 dye laser or a Ti:sapphire laser of <0.5 cm –1 line width pumped by a Millennia Prime solid-state laser (all Spectra-Physics). Nonselective fluorescence was excited by a 5 mW diode laser at 407 nm.…”

Section: Experimental and Computational Methodsmentioning

confidence: 99%

Higher Order Vibronic Sidebands of Chlorophyll a and Bacteriochlorophyll a for Enhanced Excitation Energy Transfer and Light Harvesting

2019

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Optical absorption and fluorescence spectra of molecules in condensed phases often show extensive sidebands. Originating from electron−vibrational and electron−phonon couplings, these spectral tails bear important information on the dynamics of electronic states and processes the molecules are involved in. The vibronic sidebands observed in conjugate Q y absorption and fluorescence spectra of chlorophyll a and bacteriochlorophyll a are relatively weak, characterized by the total Huang−Rhys factor which is less than one. Therefore, it is widely considered that only fundamental intramolecular modes are responsible for their formation. Here, we provide evidence for extra-long and structured fluorescence tails of chlorophyll a and bacteriochlorophyll a as far as 4000 cm −1 from respective spectral origins, far beyond the frequency range of fundamental modes. According to quantum chemical simulations, these sidebands extending to ∼960 nm in chlorophyll a and ∼1140 nm in bacteriochlorophyll a into the infrared part of the optical spectrum are mainly contributed to by vibrational overtones of the fundamental modes. Because energy transfer and relaxation processes generally depend on vibronic overlap integrals, these findings potentially contribute to better understanding of many vital photo-induced phenomena, including photosynthetic light harvesting.

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Intermolecular repulsive–dispersive potentials explain properties of impurity spectra in soft solids

Cited by 10 publications

References 29 publications

Modeling of Resonant Hole-Burning Spectra in Excitonically Coupled Systems: The Effects of Energy-Transfer Broadening

Modeling of Resonant Hole-Burning Spectra in Excitonically Coupled Systems: The Effects of Energy-Transfer Broadening

Asymmetry in the Qy Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics

Higher Order Vibronic Sidebands of Chlorophyll a and Bacteriochlorophyll a for Enhanced Excitation Energy Transfer and Light Harvesting

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