Journal ArticleDOI
ESR-Untersuchungen an Triplett-Excitonen in Anthracen- und Naphthalin-Einkristallen
Von D. Haarer,H. C. Wolf +1 more
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In this paper, the ESR spectra of optically excited triplet excitons in anthracene and naphthalene single crystals were measured at 35 GHz, 300 °K and 100 °K.Abstract:
The ESR spectra of optically excited triplet excitons in anthracene and naphthalene single crystals were measured at 35 GHz, 300 °K and 100 °K. A complete analysis of the fine structure tensor is given. The relaxation times T 1 and T 2 were investigated as a function of the orientation of the magnetic field B 0 in the crystal. It is shown that both relaxation times are determined by the modulation of the dipolar fine structure interaction due to the incoherent motion (“hopping”) of the excitons. The following values for the correlation times τc are determined: Anthracene 300 °K, τc = 3.6·10−12 sec, Naphthalene 300 °K, τc = 9.10−12 sec. At 100 °K, τc is approximately 30% shorter.read more
Citations
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Journal ArticleDOI
An exactly solvable model for coherent and incoherent exciton motion
Hermann Haken,Gert Strobl +1 more
TL;DR: In this paper, the motion of a Frenkel exciton using a Hamiltonian consisting of a completely coherent part and a fluctuating part which describes both the energy of a localized exciton and fluctuations of the transition matrix elements between different lattice sites.
Journal ArticleDOI
EPR of triplet excitions in tetracene crystals: spin polarization and the role of singlet exciton fission
L. Yarmus,J. Rosenthal,M. Chopp +2 more
TL;DR: In this paper, the room temperature electron paramagnetic resonance spectrum of triplet excitons in single-crystal tetracene is reported, and the exciton spin hamiltonian is fit to the measured angular dependence in the a'b plane.
Journal ArticleDOI
The “mini-exciton” in the C10H8 naphthalene pair in a AC10D8 host as studied by electron spin echo and odmr techniques
TL;DR: In this article, the phase memory time T M in the triplet state of the pair of two translationally inequivalent naphthalene molecules in an external magnetic field as a function of temperature was measured.
Journal ArticleDOI
The origin of optical dephasing times and line shape functions for electronic transitions to localized and delocalized states in solids
TL;DR: In this paper, a theory for optical dephasing times and the homogeneous component of the absorption line shape function to localized states and to the k=o levels of Frenkel exciton states is presented.
References
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Principles of magnetic resonance
TL;DR: In this article, the effect of changing the precession frequency of the magnetic field has been studied using NMR to study rate properties. But the effect is limited to the case of double and double resonance.
Journal ArticleDOI
Laser Generation of Excitons and Fluorescence in Anthracene Crystals
TL;DR: In this article, the authors studied the time dependence of the fluorescence intensity as a function of laser intensity, crystal temperature and excitation wavelength, and concluded that the triplet state at 14 750 cm−1 can be populated (i) by direct absorption of laser photons involving an activation energy of 350 cm− 1; (ii) via two-photon absorption, presumably leading to a vibrationally excited state of the 1B2u exciton, followed by intersystem crossing; (iii) via one−photon (second-harmonic) excitation from levels�
Journal ArticleDOI
Paramagnetic resonance absorption in naphthalene in its phosphorescent state
TL;DR: In this paper, the long principal magnetic axis in the plane of the phenanthrene molecule was taken as the x axis, the short axis was taken to be the y axis, and the normal to the plane was taken by the z axis.
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