On band shapes of electronic transitions in the multimode weak coupling limit

Abstract

The influence of multidimensional Franck-Condon (FC) active vibrational subspace on the band shapes of electronic transitions is explored in the linear weak coupling limit. Given a constant (weak) coupling coefficient, computer calculated band shapes are seen to fall into three classes depending on the number of active vibrational modes, N. For large N, the electronic band of a polyatomic molecule will have a relatively weak zero-zero absorption compared to the "side-band" absorption, which arises from a rapidly increasing density of states (DOS). For small N, a normal, weak FC progression is seen in which the peak absorption is in the zero-zero transition. The implications of the DOS/FC model are further discussed in relation to previous work. Calculations are presented to emphasize the effect of the multidimensional subspace on the relationship between the absorption band shape and the resonance Raman excitation profile.

Electronic Transitions of Polyalkylthiophenes Partially Derivatized with NLO Chromophores: A Theoretical and Experimental Study

“…For film deposition, 2 mg of the polymer were dissolved in 5 mL of freshly distilled spectrophotometric grade THF, the spinner was run at 1 500 rpm for 15 s at room temperature in clean room conditions and then the thickness of the samples was measured with a profilometer. The SHG experimental setup involved a Quantel Brilliant Q-switched Nd:YAG laser (frequency up to 10 Hz, 400 mJ Á pulse performing a Maker fringes reference experiment [6] with a quartz crystal slab (110) (d 33 …”

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Vibronic-structure tracking: A shortcut for vibrationally resolved UV/Vis-spectra calculations

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Resonance Raman and hyper‐Raman spectroscopy of organic chromophores for second‐order nonlinear optics

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