Quantum-Mechanical Phase-Interference Effects in Low-EnergyHe+-Ne andNe+-He Inelastic Collisions

Total relative emission cross sections for the production of He I, Ne I, and Ne II radiation have been measured as a function of energy in low-energy ${\mathrm{He}}^{+}$-Ne and ${\mathrm{Ne}}^{+}$-He collisions. These are the first ion-atom excitation measurements of atomic states populated through two different incoming pseudomolecular-potential curve channels. The oscillatory structure in the ${\mathrm{He}}^{+}$-Ne data can be explained in terms of phase-interference effects between potential curves at pseudocrossings occurring at large internuclear distances.