Cross sections for radiative electronic attachment to the molecules of astrophysical interest

ORAL

Abstract

Several negative ions C$_n$H$^-$ ($n=4,6,8$) and C$_n$N$^-$ ($n=1,3,5$) have been recently observed in the interstellar medium (ISM). A possible mechanism of their formation is radiative electron attachment (REA). We have developed a first-principle theoretical approach to study REA applying it to the formation of the following negative molecular ions: CN$^-$, C$_2$H$^-$, C$_3$N$^-$, C$_5$N$^-$, C$_6$H$^-$, and C$_8$H$^-$. The theoretical approach is based on the UK R-matrix calculations. Cross sections and rate coefficients for formation of these ions by REA to the corresponding neutral radicals are calculated. There is no experimental data on REA of these ions. However, using a similar approach we have also calculated cross sections for photodetachment of the negative ions and compared the obtained results with available experimental data. The good agreement with photodetachment experimental data provides a confirmation that the REA cross sections obtained in this study are also reliable. The present study suggests that the studied negative ions are unlikely be formed by REA in the ISM.

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Authors

  • Marjan Khamesian

    University of Central Florida, Orlando, FL

  • Richard Longland

    University of Tennessee, Knoxville, University of Alabama at Birmingham, Rutgers, The State University of New Jersey, Florida Intl Univ, Christopher Newport University, Jefferson Laboratory, University of North Georgia, Dahlonega GA 30597, Oak Ridge National Laboratory, Oak Ridge, TN 37831, Austin Peay State University department of physics and astronomy, Laboratoire des Verres et et Ceramiques, Institute des Sciences chimiques de Rennes, Austin Peay State University Department of Physics and Astronomy, Université de Rennes, Lehigh University, Austin Peay State University, University of Alabama, Oak Ridge National Laboratory, Auburn University, Auburn, AL, Purdue University, West Lafayette, IN, Queen's University Belfast, Belfast, United Kingdom, Harvard Smithsonian Center for Astrophysics, Boston, MA, Francis Marion University, Auburn University, Lawrence Berkeley National Laboratory, University of California, Davis, University of Alabama Huntsville, Oak Ridge National Lab, Univ of Tennessee, Knoxville, Oak Ridge National Lab, Univ of Tennessee, Knoxville, ITEP, Moscow, Baylor University, Saint Louis University, Louisiana State Univ - Baton Rouge, University of Chicago, Oak Ridge National Laboratory , Oak Ridge TN 37831, American Superconductor Corp., Westborough, MA 01581, USA, Tsinghua University, LBNL, Vanderbilt University, Laboratoire Aime Cotton, CNRS/Universite Paris-Sud/ENS-Cachan, Orsay France, Drake University, Des Moines, IA, University of Central Florida, University of South Alabama, North Carolina Central University

  • Richard Longland

    University of Tennessee, Knoxville, University of Alabama at Birmingham, Rutgers, The State University of New Jersey, Florida Intl Univ, Christopher Newport University, Jefferson Laboratory, University of North Georgia, Dahlonega GA 30597, Oak Ridge National Laboratory, Oak Ridge, TN 37831, Austin Peay State University department of physics and astronomy, Laboratoire des Verres et et Ceramiques, Institute des Sciences chimiques de Rennes, Austin Peay State University Department of Physics and Astronomy, Université de Rennes, Lehigh University, Austin Peay State University, University of Alabama, Oak Ridge National Laboratory, Auburn University, Auburn, AL, Purdue University, West Lafayette, IN, Queen's University Belfast, Belfast, United Kingdom, Harvard Smithsonian Center for Astrophysics, Boston, MA, Francis Marion University, Auburn University, Lawrence Berkeley National Laboratory, University of California, Davis, University of Alabama Huntsville, Oak Ridge National Lab, Univ of Tennessee, Knoxville, Oak Ridge National Lab, Univ of Tennessee, Knoxville, ITEP, Moscow, Baylor University, Saint Louis University, Louisiana State Univ - Baton Rouge, University of Chicago, Oak Ridge National Laboratory , Oak Ridge TN 37831, American Superconductor Corp., Westborough, MA 01581, USA, Tsinghua University, LBNL, Vanderbilt University, Laboratoire Aime Cotton, CNRS/Universite Paris-Sud/ENS-Cachan, Orsay France, Drake University, Des Moines, IA, University of Central Florida, University of South Alabama, North Carolina Central University

  • Viatcheslav Kokoouline

    University of Central Florida, Orlando, FL