Photophysics of rigidized 7-aminocoumarin laser dyes: efficient intersystem crossing from higher excited state
✍ Scribed by M.R.V. Sahyun; D.K. Sharma
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 441 KB
- Volume
- 189
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
An unusual slow rise (over z 100 ps) of fluorescence intensity from the julolidylcoumarins, coumarins 102, 314 and 334, is observed under conditions of high-intensity, pulsed laser (355 nm) excitation. The basis of this phenomenon was explored in photoquenching, time-resolved transient absorption and amplified stimulated emission studies of coumarin 3 14. The slow rise is shown to be the consequence of two photon excitation and the fluorescence rise time associated with the rate of S,-S, decay. Principal fate of S, is intersystem crossing, and the fluorescence rise time is thought to be a measure of that rate, i.e. 5 lOLo s-'.