Temperature effects on the UV–Vis electronic spectrum of trans‐stilbene

Kwasniewski, Sergiusz; François, J; Deleuze, Michaël S.

doi:10.1002/qua.10016

Cited by 17 publications

(23 citation statements)

References 76 publications

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“…The influence of thermal excitations on the absorption spectrum of 1PV was explicitly analyzed using resonance Raman spectroscopy 25 and by ZINDO/S-CI ͑Zerner's spectroscopic parameterization for intermediate neglect of differential overlap for spectroscopy͒ coupled to MD ͑molecular dynam-ics͒ simulations. 54 Nevertheless, for nPVs with nу1 a detailed investigation on the influence of thermal excitations on both the absorption and fluorescence spectra was not yet performed. Fluorescence and absorption spectra of 1PV at T ϭ4 K were recorded in solid solution 55 and under collisionfree conditions.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence and absorption spectra of oligophenylenevinylenes: Vibronic coupling, band shapes, and solvatochromism

Gierschner¹,

Mack²,

Lüer³

et al. 2002

The Journal of Chemical Physics

295

424

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Fluorescence emission and excitation spectra of para-phenylene vinylenes nPV with nϭ1 -4 styryl units are investigated experimentally and theoretically as a function of the temperature and the polarizability of the solvent. At low temperatures, the vibronic structures of the S 0 ↔S 1 emission and excitation bands are mirror symmetrical with negligible 0-0 energy gaps. The frequencies of the prominent vibrational modes are assigned to the second longitudinal acoustic phonon modes of the entire molecules and to localized carbon-carbon stretching vibrations. The complete vibronic structures of the spectra are calculated at the ab initio Hartree-Fock (HF/6-311G*) and restricted configuration interaction singles (RCIS/6-311G*) levels of theory assuming planar C 2h molecular symmetry. The theoretically predicted spectra are in good agreement with the experiments. At room temperature, a 0-0 energy gap between the first band maxima opens, and the mirror symmetry between absorption and emission is lost. The vibronic band shapes and 0-0 band gaps are successfully simulated with a combination of Gaussian and exponential broadening of the low temperature spectra. The exponential term reflects the differences in thermal population of the phenyl-vinyl torsional modes in the S 0 and S 1 electronic states. Spectral shifts upon changes in temperature and solvents are quantitatively explained by changes in the refractive index of the environment. From extrapolation of the experimental data the vertical and adiabatic transition energies of the oligomers in vacuo are obtained and compared to RCIS and semiempirical quantum chemical calculations, respectively.

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Section: Introductionmentioning

confidence: 99%

Fluorescence and absorption spectra of oligophenylenevinylenes: Vibronic coupling, band shapes, and solvatochromism

Gierschner¹,

Mack²,

Lüer³

et al. 2002

The Journal of Chemical Physics

295

424

View full text Add to dashboard Cite

show abstract

“…Even though we have simplified the structure issue for a molecule or a solid at finite temperature, the equations we obtained in this paper will find wide applications. The examples include the investigation of temperature effects on the average structure and the electronic spectra of macromolecules and the study of conduction electrons in metals and so forth [18][19][20][21].…”

Section: Discussionmentioning

confidence: 99%

Orbital approximation for the reduced Bloch equations: Fermi–Dirac distribution for interacting fermions and Hartree–Fock equation at finite temperature

Wei

Sun

2004

Physica A: Statistical Mechanics and its Applications

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In this paper, we solve a set of hierarchy equations for the reduced statistical density operator in a grand canonical ensemble for an identical many-body fermion system without or with two-body interaction. We take the single-particle approximation, and obtain an eigen-equation for the single-particle states. For the case of no interaction, it is an eigen-equation for the free particles, and solutions are therefore the plane waves. For the case with two-body interaction, however, it is an equation which is the extension of usual Hartree-Fock equation at zero temperature to the case of any finite temperature. The average occupation number for the single-particle 1 states with mean field interaction is also obtained, which has the same Fermi-Dirac distribution form as that for the free fermion gas. The derivation demonstrates that even for an interacting fermion system, only the lowest N orbitals, where N is the number of particles, are occupied at zero temperature. In addition, their practical applications in such fields as studying the temperature effects on the average structure and electronic spectra for macromolecules are discussed. 72.80.Le P ACS

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“…However we must consider that calculations neglect thermal motion effects, which can shift the calculated absorption peak. 60,61 More important, calculations are performed in vacuum while experiments are performed in solution. Solvent effects will red-shift absorption and, more significantly, fluorescence energies.…”

Section: Comparison Of Experimental and Theoretical Datamentioning

confidence: 99%

Theoretical study on oligothiophene N-succinimidyl esters: size and push–pull effects

Piacenza

Zambianchi

Barbarella

et al. 2008

Phys. Chem. Chem. Phys.

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We report a theoretical study on the optical properties of bithiophene and terthiophene N-succinimidyl esters, which have been functionalized with a methylsulfanyl group in the alpha or the beta positions. Time-dependent density functional theory (TD-DFT) and approximate coupled-cluster singles and doubles with the resolution of identity technique (RI-CC2) calculations have been performed in the ground and excited states. The RI-CC2 results for absorption and fluorescence energies are in better qualitative agreement with experiments, whereas TD-DFT does not correctly describe the higher energy part of the absorption spectra of beta-substituted bithiophenes, due to the presence of charge-transfer states. Systems functionalized at the alpha position show a large red-shift of the main absorption and fluorescence band and a larger Stokes-shift compared to the unsubstituted species. These effects are in most cases less pronounced for the beta-substituted structures. In particular, we found that the Stokes-shift of the alpha-substituted structures is larger than the one of the beta-substituted species due to a more planar orientation of the methylsulfanyl group with respect to the neighbouring thiophene in the excited state.

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Temperature effects on the UV–Vis electronic spectrum of trans‐stilbene

Cited by 17 publications

References 76 publications

Fluorescence and absorption spectra of oligophenylenevinylenes: Vibronic coupling, band shapes, and solvatochromism

Fluorescence and absorption spectra of oligophenylenevinylenes: Vibronic coupling, band shapes, and solvatochromism

Orbital approximation for the reduced Bloch equations: Fermi–Dirac distribution for interacting fermions and Hartree–Fock equation at finite temperature

Theoretical study on oligothiophene N-succinimidyl esters: size and push–pull effects

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