PHOTOPHYSICAL PROPERTIES AND ENERGY-TRANSFER DYE-LASER CHARACTERISTICS OF 7-DIETHYLAMINO-3-HETEROARYL COUMARIN IN SOLUTION

Photophysical properties and Energy transfer Dye Laser (ETDL) characte ristics of a new dye: 7-Diethyl Amino Coumarin with a Heteroaryl subst itution in the 3-position (DACH), are presented. The suitability of DA CH as a laser dye has been verified on the basis of the absorption and fluorescence characteristics in aprotic solvents. The dye laser chara cteristics of the dye pumped by the available nitrogen laser have been successfully investigated in dimethylsulfoxide by energy transfer dye laser mechanism, using coumarin 1 as a donor dye. DACH has been found to lase in the blue-green region of the visible spectrum. The experim ental and theoretical values of energy transfer rate constant (k(ET)) and the critical transfer distance (R(0)) have been calculated in two different solvents to determine the nature of energy transfer. The res ults indicate the dominance of resonance transfer in this ETDL.