Heterogeneous reactions between ions NH3+ and NH+ and hydrocarbons adsorbed on a tungsten surface. Formation of HCN+ in NH+-surface hydrocarbon collisions

Abstract

Interaction of NH3+ (ND3+) and NH+ with a hydrocarbon-covered tungsten surface kept at room temperature or heated to 150 and 300°C showed a series of reactions between the projectile ion and hydrocarbons adsorbed on the tungsten surface. Collisions with NH3+ showed formation of NH4+, HCNH+, and CH2NH2+, with NH4+ strongly prevailing at low incident energies of the projectile ion. Analogously, collisions with ND3+ showed formation of ND3H+, HCND+, and CH2ND2+ with dominant contributions of ND3H+ at low incident energies. No formation of HCN+ (DCN+) could be positively identified. In reactions with NH+, formation of HCN+ was clearly observed; the dependence of the normalized yield of HCN+ on incident energy indicated a threshold at about 40eV which might be due to an activation energy or an endothermicity of the surface reaction of about 2.4–3.2eV.