Resolution of multiexponential spectral relaxation of Yt-base by global analysis of collisionally quenched samples

Henryk Szmacinski, Ignacy Gryczynski, Joseph R. Lakowicz

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We measured the wavelength-dependent intensity decays of 4,9-dihydro-4,6-dimethyl-9-oxo-1H-imidazo-1,2a-purine (Yt-base) in propanol to determine the time-resolved emission spectra and rates of spectral relaxation. We found that resolution of the spectral relaxation times was dramatically improved by global analysis of the frequency-domain data with increasing amounts of the collisional quencher CCl4. Collisional quenching preferentially decreases the longer-lived relaxed component of the emission, thereby increasing the fractional contribution of the incompletely relaxed portion of the emission. The data could not be explained by a single spectral relaxation time, and at least two relaxation times are needed to describe the time-dependent emission center of gravity of Yt-base.

Original languageEnglish
Pages (from-to)177-185
Number of pages9
JournalJournal of Fluorescence
Issue number3
StatePublished - 1 Jan 1996


  • Fluorescence decay
  • Frequency-domain fluorometry
  • Solvent effects
  • Solvent relaxation
  • Time-resolved emission spectra


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