Energy-dependent ion-yield curve for C− from electron–OCS collisions

Obtain the energy-dependent ion-yield curve for the C− anion produced by collisions of 0–45 eV electrons with carbonyl sulfide (OCS), which was not measured in this study because the signal was too weak to extract a yield as a function of incident electron energy.

Background

C− formation in electron–OCS collisions is observed only in the ion-pair dissociation regime, with the thermochemical threshold for the SO+ + C− channel estimated at 10.58 eV. Despite detecting C− at higher energies, the signal intensity was insufficient to construct an energy-resolved ion-yield curve.

A measured ion-yield curve would enable a more precise determination of the appearance threshold, energy dependence, and potential contributions from competing pathways, complementing the thermochemical estimates and comparisons with related systems such as CO2.