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dc.contributor.authorNijegorodov, N
dc.contributor.authorZvolinski, V
dc.contributor.authorLuhanga, P V C
dc.contributor.authorMabbs, R
dc.contributor.authorAhmad, J
dc.date.accessioned2008-10-22T07:09:56Z
dc.date.available2008-10-22T07:09:56Z
dc.date.issued2006
dc.identifier.citationNijegorodov, 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. 196-205en
dc.identifier.issn1386-1425
dc.identifier.urihttp://hdl.handle.net/10311/247
dc.description.abstractThe 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.isoenen
dc.publisherElsevier Science Ltd. www.elsevier.com/locate/saaen
dc.subjectSingleen
dc.subjectDouble and triple fluorescenceen
dc.subjectLaser actionen
dc.titlePhotochromism, anomalous multi-banded fluorescence and laser properties of some amino- and tosyl-amino derivatives of oxadiazoleen
dc.typeArticleen


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