Surface-induced reactions of acetone cluster cations

Abstract

The occurrence of two different chemical reactions initiated by the surface impact of acetone dimer, trimer, and tetramer cations (energy 20–70 eV) on a stainless-steel surface (covered with hydrocarbons) was observed. The reaction product is the protonated acetone ion, formed in (i) an intracluster ion–molecule reaction, and in (ii) a hydrogen pickup reaction of the cluster ion with the surface material. Only the monomer product ions (and small amounts of their dissociation products) could be observed; the spectra did not show any presence of clustered product ions. A simple model based on the Brauman double-well potential is suggested to explain the formation of the two product ions. In accordance with predictions from molecular dynamics simulations, this appears to be the first observation of competitive chemical reactions of a cluster ion driven by energy transfer in a surface collision.

Surface-induced dissociation and reactions of cations and dications C7H8+/2+, C7H7+/2+ and C7H62+: Dependence of mass spectra of product ions on incident energy of the projectiles

“…The relative abundance of product ions in dependence on incident projectile ion energy (CERMS curves) were measured with the tandem mass spectrometer apparatus BESTOF described in detail in our earlier papers [27,28]. It consists of a double focusing two-sector-field mass spectrometer (reversed geometry) combined with a linear time-of-flight mass spectrometer.…”

Collision-induced fragmentation and neutralization of methanol cluster cations

“…This way, for the first time it is possible to investigate the dynamics and the reactivity of physical and chemical processes under extreme temperatures and pressures under controlled and clean, well-defined conditions. So far, however, due to the inherent experimental complexity, investigations of chemical processes taking place during cluster-surface collisions are rare [30][31][32][33][34][35][36][37]. Obviously, more detailed experimental results are necessary for a deeper understanding of the ultrafast chemical dynamics in cluster-surface collisions.…”

Surface collisions of small cluster ions at incident energies 10–102eV

“…H-atom transfer reaction and formation of a protonated product is a frequent process in collisions of open-shell molecular ions with hydrocarbon-covered surfaces [6]. An analogous process was observed in collisions of stoechiometric acetone [35,36] and acetonitrile [37] cluster ions with hydrocarbon-covered surfaces. The reactions and their competition with an intra-cluster surface-induced protonation reaction will be discussed later on in Section 3.2.…”