Energy Partitioning in Collisions of Slow Polyatomic Ions with Surfaces: Ethanol Molecular Ions on Stainless Steel Surfaces

Mass spectra and translational and angular distributions of product ions formed in interactions of 13–33 eV ethanol molecular ions (C₂H₆O^+•), as well as C₂H₇O⁺ and C₂H₅O⁺ ions, with a stainless steel surface were investigated to determine the partitioning of energy in the collisions with the surface. Distribution functions were derived from the data for the energy fractions going into internal excitation of the projectile, product translational energy and that absorbed by the surface. The peak values of the three energy fractions increased linearly with the incident projectile energy but their mutual ratios did not change. With increasing incident angle, the fraction of internal excitation did not change, the fraction of product translational energy increased, and the fraction absorbed by the surface correspondingly decreased. The ion survival probability increased substantially with increasing incident angle.