Interferences in electron emission from O2 by 30 MeV O5,8+ impact

Interference structures in the ejected electron spectra for 30 MeV O5,8+ + O2 are investigated. The measured electron yields were studied for electron energies from 5 to 400 eV and observation angles of 30o, 60o, 90o, 120o and 150o with respect to the incident beam direction. Experimental molecular cross-sections were normalized to theoretical molecular one-center cross-sections revealing oscillatory structures suggestive of secondary interferences as evidenced by the independence on the observation angle. An oscillation interval for 30 MeV O5,8+ + O2 of Δk ∼ 4 a.u. is found, a value two times larger than that previously observed for 3 MeV H+ + N2. No obvious evidence for primary Young-type interferences was seen.