Inhomogeneous/homogeneous broadenings

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... 

Why is the two-photon ionization spectrum so broad Is the spectrum mainly homogeneously broadened or inhomogeneously broad-... 

Isotropic scattering In addition to the dephasing time T2, the correlation time rc of the purely vibrational relaxation process can be measured, providing quantitative information on the question of homogeneous/inhomogeneous line broadening. 

One way of determining whether the line is broadened homogeneously or inhomogeneously, is to irradiate and saturate a specific spot in the line with a large, coherent H field. Immediately after the irradiation, the line is detected either by cw or pulse FT NMR and an inhomogeneous line will have a "hole" burned into it (Bloembergen, et al., 1948). 

Figure 2 (A) Sketch of a disordered lattice doped with probe molecules (black bars). Note that each probe molecule has a different environment. (B) Inhomogeneous line broadening the inhomogeneous line of width Aco is built from an ensemble of homogeneous lines of width Aft>h.

Tokmakoff A and Fayer M D 1995 Homogeneous vibrational dynamics and inhomogeneous broadening in glass-forming liquids infrared photon echo experiments from room temperature to 10 KJ. Chem. Phys. 103 2810-26... 

If dye molecules are embedded into an amorphous matrix, preferably transparent polymers, greatly and inbornogenously broadened spectral lines are observed. This broadening is caused by the energetic interaction of the dye molecules with the locally different environment in the polymer matrix. The ratio of the homogenous initial line width of the dye molecule T to the inhomogenous line width of the dye in the polymer T ranges from 1 10 to 1 10 . ... 

N. Steigerwald, M. L. and Brus, L. E. (1988) Electronic states of semiconductor clusters - homogeneous and inhomogeneous broadening ofthe optical-spectrum./. Chem. Phys., 89, 4001 1011. 

Homotransfer between chemically identical molecules in polar ambience had attracted attention during the last years [27]. This transfer has the same mechanism as FRET, but due to the presence of inhomogeneous broadening of spectra (see below), it is not random as in homogeneous systems, where it is directed from... 

FIGURE 4.2 Linewidth increase with temperature for an S = 1/2 system. The linewidth of a feature in the low-spin heme spectrum from cytochrome a in bovine heart cytochrome oxidase has been fit as a convolution of a constant component from inhomogeneous broadening and a temperature-dependent component from homogeneous broadening (Hagen 2006). (Reproduced by permission of The Royal Society of Chemistry.)... 

The last mentioned dynamical capability of lasers is in its infancy. It is possible in principle to make optical measurements which are analogous to coherent NMR measurements, and thereby to observe homogeneous linewidths in inhomogeneously broadened systems, to measure optical or vibrational Ti and T2 relaxation times directly, and to observe quantum recurrences. 

Homogeneous and inhomogeneous band broadening. Red-edge effects... 

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