Paul-trap resonance in He+–He collisions

Abstract

Single-electron excitation in He+–He collisions is investigated in the 30–50 keV range, where the excitation cross-sections haveresonance-like maxima. By measuring anticrossing spectra, we show that the levels of He I with are populated effectively and coherently in this energy range. The superposition states ofthe excited electron resulting from the collision process are identified as the parabolic Starkstates with the largest electric dipole moments. The results are explained with thePaul-trap model and saddle dynamics.