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      https://www.ias.ac.in/article/fulltext/jcsc/119/04/0277-0282

    • Keywords

       

      CH3CFCl2; photodissociation; Lyman-𝛼; laser-induced fluorescence.

    • Abstract

       

      The collision-free, room temperature gas-phase photodissociation dynamics of CH3CFCl2 (HCFC-141b) was studied using Lyman-𝛼 laser radiation (121.6 nm) by the laser photolysis/laserinduced fluorescence `pump/probe’ technique. Lyman-𝛼 radiation was used both to photodissociate the parent molecule and to detect the nascent H atom products via ($2p^2$P → $1s^2$S) laser-induced fluorescence. Absolute H atom quantum yield, $\phi_H = (0.39 \pm 0.09)$ was determined by calibration method in which CH4 photolysis at 121.6 nm was used as a reference source of well-defined H atom concentrations. The line shapes of the measured H atom Doppler profiles indicate a Gaussian velocity distribution suggesting the presence of indirect H atom formation pathways in the Lyman-𝛼 photodissociation of CH3CFCl2. The average kinetic energy of H atoms calculated from Doppler profiles was found to be $E_{\text{T(lab)}} = (50 \pm 3)$ kJ/mol. The nearly statistical translational energy together with the observed Maxwell-Boltzmann velocity distribution indicates that for CH3CFCl2 the H atom forming dissociation process comes closer to the statistical limit.

    • Author Affiliations

       

      Almuth Laeuter1 Hans-Robert Volpp1 Jai P Mittal2 Rajesh K Vatsa2

      1. Physikalisch-Chemisches Institut der Universitaet Heidelberg, Im Neuenheimer Feld 253, D-69120 Heidelberg, Germany
      2. Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085
    • Dates

       
  • Journal of Chemical Sciences | News

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