Study of molecular parameters of 7-ethylamino-4-trifluoromethyl coumarin: concentration dependence

✍ Scribed by Sujata Sanghi; D. Mohan

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 279 KB
• Volume: 52
• Category: Article
• ISSN: 1386-1425
• DOI: 10.1016/0584-8539(96)01661-3

✦ Synopsis

Molecular parameters, viz. absorption [a0~(1)

]/emission [a~(1)] cross-sections, threshold intensity (Ip~h)/threshold pump rate (Wp,h), and fluorescence lifetime (r)/excited to ground state rate constant (As, ~s.) have been estimated in the case of 7 4 ethylamino trifluoromethyl coumarin (C-500) dye molecule in ethanol in the concentration range from 10 mM to 0.01 mM under N 2 laser excitation via optical gain studies. The results obtained at higher concentration ( >~ l mM) is understood to be due to exciplex formation. The dependence of small signal gain coefficient and saturation parameter on the dye concentration have also been correlated with the variation of fluorescence lifetime and hence attributed to radiation trapping, concentration quenching and exciplex formation.