Radiative electron attachment to molecules of astrophysical interest. Benchmark study of CN$^-$.

ORAL

Abstract

We develop a first-principles approach to study the process of radiative electron attachment (REA) to linear molecules of astrophysical interest $Mol +e^- \to Mol^- + \hbar\omega$. ($Mol^-$ = C$_n$H$^-$, C$_n$N$^-$). The approach is based on accurate ab initio calculations of electronic bound and continuum states of the negative ion. The electronic continuum states are obtained with the complex-Kohn variational method. A preliminary calculation for the formation of the simplest observed ion, CN$^-$, by REA gave a low rate coefficient. We will present also a preliminary result for the C$_4$H$^-$ formation by REA. For this molecule, the REA rate coefficient is expected to be somewhat larger due to the Renner-Teller non-adiabatic coupling that should enhance electron capture. The goal of this study is to answer the question if negative molecular ions C$_n$H$^-$ and C$_n$N$^-$ recently observed in the interstellar space could indeed be formed by REA as previously suggested.

*This work is supported by the DOE Office of Basic Energy Science and the National Science Foundation, Grant No's PHY-08-55092 and PHY-08-55622.

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Authors

  • Viatcheslav Kokoouline

    • Dep. of Physics, University of Central Florida
    • Department of Physics, University of Central Florida

  • Nicolas Douguet

    • University of California Davis
    • Dep. of Chemical Engineering and Materials Science, Univ. of California at Davis
    • Department of CHMS, University of California at Davis

  • Olivier Dulieu

    • Laboratoire Aime Cotton, Universite Paris XI

  • Maurice Raoult

    • Laboratoire Aime Cotton, Universite Paris XI

  • Ann E. Orel

    • University of California Davis
    • UC Davis
    • UCDavis
    • Dep. of Chemical Engineering and Materials Science, Univ. of California at Davis
    • Dept. of Chemical Engineering and Materials Science, University of California, Davis