Eur. Phys. J. D (2012) 66: 181
https://doi.org/10.1140/epjd/e2012-20643-2

Regular Article

Low energy electron induced dissociation in condensed diallyl disulfide

¹ Department of Chemistry, Faculty of Science, Ege University, 35100 Bornova, Izmir, Turkey
² Department of Nuclear Medicine and Radiobiology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, J1H 5N4 Quebec, Canada

^a e-mail: yeliz.yildirim@ege.edu.tr

Received: 2 November 2011
Received in final form: 19 March 2012
Published online: 12 July 2012

Abstract

Using a high sensitivity Time of Flight mass analyser we have measured the electron stimulated desorption (ESD) of anions and cations from multilayer thin films of diallyl disulfide (DADS) formed by condensation onto Pt and Kr substrates. Measurements were performed as a function of incident electron energy (E_i), film thickness and effective incident current. For E_i ≲ 15 eV the desorption yields of anions are the result of dissociative electron attachment (DEA) via several transient negative ions often associated with electron capture into C-S and S-S σ* bonds. The minimum incident energies observed for desorption of the anionic fragments H⁻, S⁻, CH₂CHCH^-₂, and CH₂CHCH₂S⁻ are compared to theoretical bond dissociation energies calculated using DFT methods. In comparison to gas-phase electron impact mass spectra, the yield of cationic fragments are dominated by desorption of low mass fragments although similar species are observed in both cases. Electron impact at higher electron energies on thicker films of DADS enhances desorption of larger fragment ions, including those formed by the scission and formation of multiple bonds.