Eur. Phys. J. D (2012) 66: 73
https://doi.org/10.1140/epjd/e2012-20651-2

Regular Article

Low energy H⁻ production by electron collision with small hydrocarbons

Jožef Stefan Institute and Association EURATOM-MHEST, Jamova cesta 39, 1000 Ljubljana, Slovenia

^a e-mail: iztok.cadez@ijs.si

Received: 8 November 2011
Received in final form: 24 January 2012
Published online: 27 March 2012

Abstract

The production of low-energy H⁻ by electron impact with CH₄, C₂H₂, C₂H₄, C₂H₆ and C₃H₈ has been studied within electron energy range 0−20 eV. The dissociative electron attachment and dipolar dissociation (also known as ion pair production) are contributing to formation of H⁻ in this energy range. A special ion extraction system for collection of low-energy light ions was used. Low-energy H⁻ production rates for all studied molecules are found lower yet similar to those for hydrogen at 14 eV dissociative attachment maximum. A vertical onset of ion yield is observed for the dissociative attachment in CH₄, C₂H₂, and C₃H₈. The production rate of H⁻ through the dipolar dissociation is observed to be high in the case of C₂H₄.