title: Apparent velocity threshold in the electronic stopping of slow hydrogen ions in LiF.
abstract: The electronic energy loss of hydrogen ions (protons and deuterons) in thin supported films of LiF has been studied in backscattering geometry for specific energies from 700 eV/u to 700 keV/u, using Rutherford backscattering spectroscopy and time-of-flight low-energy ion scattering spectroscopy. For specific energies below 8 keV/u, our data confirm velocity proportionality for the stopping cross section epsilon (like in a metal) down to 3.8 keV/u, as observed previously for protons and antiprotons despite the large band gap (14 eV) of LiF. Below 3.8 keV/u, the present results indicate an apparent velocity threshold at about 0.1 a.u. for the onset of electronic stopping.
authors.affiliation: Institut für Experimentalphysik, Johannes-Kepler Universität, Altenbergerstr. 69, A-4040 Linz, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Draxler
authors.forename: S P
authors.initials: SP
authors.lastname: Chenakin
authors.forename: S N
authors.initials: SN
authors.lastname: Markin
authors.forename: P
authors.initials: P
authors.lastname: Bauer