Abstract
We observed the steady state fluorescence anisotropy spectra of indole and N-acetyl-L-tryptophanamide (NATA) resulting from one- (OPE) and two-photon excitation (TPE) of fluorescence. The anisotropy spectra for OPE and TPE are remarkably different, suggesting that the cross sections for relative absorption of the 1La and 1Lb state are different for one- and two-photon absorption. Frequency-domain time-resolved anisotropy decays confirm the unusual value of the time-zero anisotropies. Comparison of the OPE and TPE anisotropy spectra should allow a more critical evaluation of the accepted 1La-1Lb model for tryptophan and protein fluorescence.
Original language | English |
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Pages (from-to) | 282-287 |
Number of pages | 6 |
Journal | Chemical Physics Letters |
Volume | 194 |
Issue number | 4-6 |
DOIs | |
State | Published - 3 Jul 1992 |