Dissociative electron attachment to gas-phase formamide

• Published in: Physical chemistry chemical physics : PCCP 2011-07, Vol.13 (26), p.12305-12313
• Main Authors: HAMANN, T, EDTBAUER, A, FERREIRA DA SILVA, F, DENIFL, S, SCHEIER, P, SWIDEREK, P
• Format: Article
• Language: English
• Subjects: Beams (radiation); Channels; Chemistry; Derivatives; Electron attachment; Energy of dissociation; Energy use; Exact sciences and technology; Fragments; General and physical chemistry; Physical chemistry
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c1cp20833k

Dissociative electron attachment (DEA) to gaseous formamide, HCONH(2), has been investigated in the energy range between 0 eV and 18 eV using a crossed electron/molecule beam technique. The negative ion fragments have been comprehensively monitored and assigned to molecular structures by comparison with the results for two differently deuterated derivatives, namely 1D-formamide, DCONH(2), and N,N,D-formamide, HCOND(2). The following products were observed: HCONH(-), CONH(2)(-), HCON(-), OCN(-), HCNH(-), CN(-), NH(2)(-)/O(-), NH(-), and H(-). NH(2)(-) was also separated from O(-) by using high-resolution negative ion mass spectrometry. Four resonant dissociation channels can be resolved, the strongest ones being located between 2.0 and 2.7 eV and between 6.0 and 7.0 eV. CN(-) as the most abundant fragment and HCONH(-) are the dominant products of the first of these two resonances. The most important products of the latter resonance are NH(2)(-), CN(-), H(-), CONH(2)(-), and OCN(-). It is thus found that the loss of neutral H is a site-selective process, dissociation from the N site taking place between 2.0 and 2.7 eV while dissociation from the C site occurs between 6.0 and 7.0 eV. The suitability of these reactions and thus of formamide as an agent for electron-induced surface functionalisation is discussed.