OBSERVATION OF MIXED-PARITY ELECTRIC-DIPOLE OSCILLATIONS IN CHARGE-TRANSFER TO THE N=2 HYDROGEN LEVELS BY FAST PROTONS IN GASES

We find evidence for strong, collision-averaged excitation coherence between 2s and 2p0 amplitudes in charge transfer by fast protons (vi2-3 a.u.) undergoing single collisions in He, Ar, and O2. Quantum beat difference signals in Lyα (Eck beats) induced by reversible electric fields have amplitudes very similar to those seen earlier in C targets, supporting a last-layer" (gas-layer?) hypothesis. © 1979 The American Physical Society."