Absorption inhomogeneously broadened

Pullerits T, Visscher K J, Hess S, Sundstrom V, Freiberg A, Timpmann K and Van Grondelle R 1994 Energy-transfer in the inhomogeneously broadened core antenna of purple bacteria-a simultaneous fit of low-intensity picosecond absorption and fluorescence kinetics Biophys. J. 66 236-48... 

Loring RA (1990) Statistical mechanical calculation of inhomogeneously broadened absorption line shapes in solution. J Phys Chem 94 513-515... 

The width of a band in the absorption spectrum of a chromophore located in a particular microenvironment is a result of two effects homogeneous and inhomogeneous broadening. Homogeneous broadening is due to the existence of a continuous set of vibrational sublevels in each electronic state. Inhomogeneous broadening results from the fluctuations of the structure of the solvation shell... 

Site-selection spectroscopy Maximum selectivity in frozen solutions or vapor-deposited matrices is achieved by using exciting light whose bandwidth (0.01-0.1 cm-1) is less than that of the inhomogeneously broadened absorption band. Lasers are optimal in this respect. The spectral bandwidths can then be minimized by selective excitation only of those fluorophores that are located in very similar matrix sites. The temperature should be very low (5 K or less). The techniques based on this principle are called in the literature site-selection spectroscopy, fluorescence line narrowing or energy-selection spectroscopy. The solvent (3-methylpentane, ethanol-methanol mixtures, EPA (mixture of ethanol, isopentane and diethyl ether)) should form a clear glass in order to avoid distortion of the spectrum by scatter from cracks. 

Section 3.5.1 described the various effects observed upon excitation at the red-edge of the absorption spectrum. In particular, a lack of energy transfer was first observed by G. Weber (1960) (and is called Weber s effect for this reason). This effect can be explained in terms of inhomogeneous broadening of spectra. In a rigid polar solution of fluorophores that are close enough to undergo non-radiative en-... 

Fig. 9. The efTect of the dipole-dipole interaction on inhomogeneously broadened infrared absorption peaks. Without and with the interaction turned on for peaks with I, a low frequency tail, II, a symmetric Gaussian distribution and III, a high frequency tail. (Adaptedfrom Persson...

Fig. 10. The infrared absorption peak of a full monolayer of CO physisor-bed on an Al(lOO) surface at 30 K. No ordered structures ate formed and the peak is inhomogeneously broadened. The dotted line is a Gaussian distribution. (Reproduced by permission from Ryberg. )...

Molecules in crystals or dispersed in host lattices are often present in a range of environments, and this results in a broadening of the electronic absorption spectrum. Such an inhomogeneously broadened absorption band (envelope of transitions) may be considered as a superposition of several distinguishable sites. A narrow line laser can saturate one of the transitions under the envelope and the corresponding molecules will no longer take part in the absorption process. This phenomenon is referred to as hole... 

In order to clarify the vibrational dynamics on the PES of the E+ electronic state of OCS, we attempted to record a high-resolution lE+-lE+ absorption profile of OCS free from the inhomogeneous broadening by introducing a technique of PHOFEX spectroscopy with a tunable high-resolution VUV laser light source [7, 9, 10]. 

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