Resolution of Electronic States from Polarization Spectra

Resolution of Electronic States from Polarization Spectra 

The complex anisotropy spectrum of indole was used to determine the absorption spectra corresponding to the 5 — L, and So—i La transitions. We present this example because of its didactic value and its importance for a detailed understanding of the fluorescence from tryptophan residues in proteins (Chapter 16). At any excitation wavelength X, the observed anisotropy is 

Using P = 90°, one obtaiiis ms = -4klS. These values of m and ms are used in Bq. [10.21], along with die restriction that the total fractional absoqrtion is nni ( g(X)-f/ )= 1], to calculate the fractiooalabsoaplion rtf 

295-300-nm excitation is used when the Intrinsic tryptophan emission of proteins is studied. This example illustrates how polarization spectra reveal the electronic properties of fluorophores. 

Finally, the absorption spectrum of each state is given by 

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A. Resolution of Electronic States from Polarization Spectra... 

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