• A comparative study of the spectroscopic features of the low-lying electronic states of H2F+ and H2Cl+ ions

    • Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/jcsc/122/02/0259-0269

    • Keywords

       

      Configuration interaction; electronic states; transition moment.

    • Abstract

       

      Configuration interaction studies of H2F+ and H2Cl+ ions, using 6-311G ($3d$, $3p$) basis sets, have revealed several interesting differences in their spectral behaviour. Both of them are having bent ground state (1A1) equilibrium geometries, but there is a huge difference (∼ 1.93 eV) between their energy barrier to linearity. Their first two excited states are found to be linear ${}^3\Pi_u$ and ${}^1\Pi_u$ states, correlating to 3B1/3A1 and 1B1/1A1 Renner-Teller pairs, respectively, in the C2v symmetry. Considering only the allowed singlet-singlet transitions at the ground state equilibrium geometry, the lowest energy transitions found to have transition moment values of 0.65 D and 0.48 D for H2F+and H2Cl+, respectively, appearing in the far UV region. Conical intersections take place during the symmetrical stretching of two H-Cl bonds in the chloronium ion for the first two pairs of excited states (11A2/11B1 and $1^1$A2/$1^1$B1) in the C2v symmetry. This intersection may initiate pre-dissociation from the upper bound adiabatic 1A″ state to the lower repulsive 1A" state in the C$_s$ symmetry. Fluoronium ion is expected to dissociate via a single electronic state due to the absence of such intersection.

    • Author Affiliations

       

      Anjan Chattopadhyay1

      1. Chemistry Group, Birla Institute of Technology and Science (BITS), Pilani - Goa Campus, Goa 403 726
    • Dates

       
  • Journal of Chemical Sciences | News

© 2022-2023 Indian Academy of Sciences, Bengaluru.