Light vibronic coupling

Kuki M, Nagae H, Cogdell RJ, Shimada K and Koyama Y (1994) Solvent effect on spheroidene in nonpolar and polar solutions and the environment of spheroidene in the light-harvesting complexes of Rhodobacter sphaeroides 2.4.1 as revealed by the energy of the Ag —> By absorption and the frequencies of the vibronically couple C=C stretching Raman lines in the A and 2 Af states. Photochem Photobiol 59 116-124... 

The description of the radiationless processes which lead to the transfer of excitation energy from one excited state to another in heavy metal complexes has been discussed by several authors (JI, 17, 22). Spin-orbit coupling must be included in the description of the initial and final states for the radiationless process but may also contribute to the coupling terms responsible for this process (II, 17). There are also vibronic coupling terms which arise from breakdown of the Bom-Oppen-heimer approximation which presumably play some role in radiationless energy transfer processes in both heavy- and light-atom molecules (II, 17). Beyond these electronic terms, there are vibrational contributions to the rate constant for a radiationless process, and these contributions are generally expressed as Franck-Condon factors (II). 

Advantages of the two-photon laser spectroscopy are as follows high resolution, tolerance of infrared light by objects under investigation, different selection rules, and vibronic coupling. The last feature allows simultaneous accomplishment of two-photon and one-photon excitations. 

New biphenyl derivative with planar phenyl-phenyl conformation in crystal at room temperature exhibits highly efficient UV light-emitting, J. Phys. Chem. B, 108, 9571-9573 (2004) (c) J. Gierschner, H.-G. Mack, L. Ltier, D. Oelkrug, Fluorescence and absorption spectra of oligophenylenevinylenes vibronic coupling, band shapes and solvatochromism, J. Chem. Phys., 116, 8596-8609 (2002). 

Special realizations of vibronic coupling systems, such as occur for well-localized, weakly coupled molecular subsystems have been touched upon only briefly, in Sect. 6.1.2.5. Another special case, that of light-induced Coins [99,100] has not been discussed above, but is expected to emerge as highly relevant in strong laser fields in the future. This may, of course, also apply to other realizations of specific sysfems, and likewise regarding their experimental detection. 

Alexandrite, the common name for Cr-doped chrysoberyl, is a laser material capable of continuously tunable laser output in the 700-800 nm region. It was established that alexandrite is an intermediate crystal field matrix, thus the non-phonon emitting state is coupled to the 72 relaxed state and behaves as a storage level for the latter. The laser-emitted light is strongly polarized due to its biaxial structure and is characterized by a decay time of 260 ps (Fabeni et al. 1991 Schepler 1984 Suchoki et al. 2002). Two pairs of sharp i -lines are detected connected with Cr " in two different structural positions the first near 680 nm with a decay time of approximately 330 ps is connected with mirror site fluorescence and the second at 690 nm with a much longer decay of approximately 44 ms is connected with inversion symmetry sites (Powell et al. 1985). The group of narrow lines between 640 and 660 nm was connected with an anti-Stokes vibronic sideband of the mirror site fluorescence. 

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