Steady-state absorption and fluorescence study: Dipole moments of coumarins
نویسندگان
چکیده
The absorption and fluorescence spectra of 7-dimethylamino cyclopenta [c] coumarin (C138) and 4-methyl-piperidino [g] coumarin (C339) dyes were measured in neutral, aprotic and protic solvents. Solvatochromic shifts of absorption and fluorescence as a function of different solvent polarity parameters (bulk as well as microscopic) were analyzed for these dyes and the ground state dipole moment (μg) and the first excited singlet state dipole moment (μe) were estimated to be μg = 2.2 and 3.42 D and μe = 4.58 and 5.2 D, respectively, for C138 and C339. The dipole moment values of μg = 3.4 D and μg = 3.8 D were also obtained for C138 and C339 respectively from abinitio calculations. The results are compared and discussed.
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