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dc.contributor.author Nijegorodov, N
dc.contributor.author Zvolinski, V
dc.contributor.author Luhanga, P V C
dc.contributor.author Mabbs, R
dc.contributor.author Ahmad, J
dc.date.accessioned 2008-10-22T07:09:56Z
dc.date.available 2008-10-22T07:09:56Z
dc.date.issued 2006
dc.identifier.citation Nijegorodov, N. et al. (2006) Photochromism, anomalous multi-banded fluorescence and laser properties of some amino- and tosyl-amino derivatives of oxadiazole. Spectrochimica Acta Part A. Vol. 65, No. 1. pp. 196-205 en
dc.identifier.issn 1386-1425
dc.identifier.uri http://hdl.handle.net/10311/247
dc.description.abstract The multi-banded fluorescence and laser properties of 11 new amino- and tosylamino derivatives of 2,5-di(phenyl)-1,3,4-oxadiazole and oxadiazole in various solvents at 293K are reported. All the compounds investigated possess intra-molecular hydrogen quasi-bond (IHB) of 4.6–5.2 kcal mol−1 in the ground state. In the excited state they can undergo protolytic dissociation or intra-molecular photon-initiated transfer of proton and reveal anomalous fluorescence which cannot be explained within the framework of the Kasha and Kasha–Vavilov rules. Depending upon the excitation wavelength, solvent, concentration and pH of the medium, the compounds studied show a single, double, triple or even a four-banded fluorescence, which has not been reported earlier. The nature of multi-banded fluorescence is explained in terms of the possible photochromic processes in excited states. Quantum yields and decay times of the different fluorescence bands are reported. Anomalous dependence of quantum yield upon concentration of the solution is observed. Laser properties of the compounds studied are carefully tested. Laser action based on the fluorescence of the so-called bi-radical molecules is reported. Various possible arrangements of singlet and triplet levels of compounds investigated are discussed. en
dc.language.iso en en
dc.publisher Elsevier Science Ltd. www.elsevier.com/locate/saa en
dc.subject Single en
dc.subject Double and triple fluorescence en
dc.subject Laser action en
dc.title Photochromism, anomalous multi-banded fluorescence and laser properties of some amino- and tosyl-amino derivatives of oxadiazole en
dc.type Article en


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