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      https://www.ias.ac.in/article/fulltext/jcsc/114/06/0675-0686

    • Keywords

       

      Sulphur dioxide; photodissociation dynamics; oxygen atom; VUV-LIF; quantum yield

    • Abstract

       

      The dynamics of formation of oxygen atoms after UV photoexcitation of SO2 in the gas-phase was studied by pulsed laser photolysis-laser-inducedfluorescence ‘pump-and-probe’ technique in a flow reactor. SO2 at room-temperature was excited at the KrCl excimer laser wavelength (222.4 nm) and O(3Pj) photofragments were detected under collision-free conditions by vacuum ultraviolet laser-induced fluorescence. The use of narrow-band probe laser radiation, generated viaresonant third-order sum-difference frequency conversion of dye laser radiation in Krypton, allowed the measurement of the nascent O(3Pj=2,1,0) fine-structure state distribution:nj=2/nj=1/nj=0 = (0.88 ± 0.02)/(0.10 ± 0.01)/(0.02 ± 0.01). Employing NO2photolysis as a reference, a value of Φ0(3P) = 0.13 ± 0.05 for the absolute O(3P) atom quantum yield was determined. The measured O(3P) quantum yield is compared with the results of earlier fluorescence quantum yield measurements. A suitable mechanism is suggested in which the dissociation proceeds via internal conversion from high rotational states of the initially excited SO2(~C1B2 (1, 2, 2) vibronic level to nearby continuum states of the electronic ground state.

    • Author Affiliations

       

      Mohammed Abu-Bajeh1 Melanie Cameron2 Kyung-Hoon Jung3 Christoph Kappel4 Almuth Läuter1 Kyoung-Seok Lee3 Harip Upadhyaya5 Rajesh K Vatsa5 Hans-Robert Volpp1

      1. Physikalisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 253, Heidelberg - D-69120, Germany
      2. Division of Atmospheric Chemistry, Max-Planck-Institut für Chemie, Mainz - D-55020, Germany
      3. Department of Chemistry and Molecular Science Institute (BK21), Korea Advanced Institute of Science and Technology (KAIST), Yusung-Gu, Taejon - 305-701, Korea
      4. Institut für Physikalische Chemie der Universität Göttingen, Göttingen - D-37075, Germany
      5. Chemistry and Isotope Group, Bhabha Atomic Research Center, Mumbai - 400 085, India
    • Dates

       
  • Journal of Chemical Sciences | News

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