Oscillations observed in electrons and scattered protons from 30-100 keV protons transiting a Si/Lexan/C layered foil

A layered foil of 4.5 μg/cm ² Si, 3.6 μg/cm ² Lexan, and 1.0 μg/cm ² C was bombarded by protons between 30 and 100 keV. The electron yields from the Si and C surfaces at θ = 0° (unscattered), 45° (forward), and 135° (backward) with respect to the beam direction were measured at proton energies 30, 60 and 90 keV. The scattered-proton yield and electron yield at θ = 0° were measured as functions of incident proton energy between 30 and 100 keV. The results exhibited oscillatory structures in the dependency of both the differential scattered proton yield and differential electron yield on the incident proton energy, which we interpret as due to interactions between 1s state of H and 2p state of C, and between 1s state of H and 3p state of Si. The respective effective interaction energies at the mixing region of internuclear distance are 304 eV-Å and 346 eV-Å. We also confirmed that production of electrons and setting of charge state of the scattered ion to be in the last atomic layer of the exit surface of the target, and the interactions between the states of H and C, or and Si shuold be carried out in the bulk of the last atomic layer of the exit surface.