title: Electron impact induced anion production in acetylene.
abstract: A detailed experimental investigation of electron induced anion production in acetylene, C2H2, in the energy range between 1 and 90 eV is presented. The anions are formed by two processes in this energy range: dissociative electron attachment (DEA) and dipolar dissociation (DD). DEA in C2H2 is found to lead to the formation of H(-) and C2(-)/C2H(-) through excitation of resonances in the electron energy range 1-15 eV. These anionic fragments are formed with super thermal kinetic energy and reveal no anisotropy in the angular distributions. DD in C2H2 leads to the formation of H(-), C(-)/CH(-) and C2(-)/C2H(-) with threshold energies of 15.7, 20.0 and 16.5 eV respectively. The measured anion yields have been used to calculate anion production rates for H(-), C(-)/CH(-) and C2(-)/C2H(-) in Titan's ionosphere.
authors.affiliation: The Open University, Department of Physical Sciences, Walton Hall, Milton Keynes, MK7 6AA, UK. ewelina.szymanska@open.ac.uk.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Szymańska
authors.forename: Iztok
authors.initials: I
authors.lastname: Čadež
authors.forename: E
authors.initials: E
authors.lastname: Krishnakumar
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Mason