“…Over the entire velocity range, the different H and He isotopes have the same value of f E at the same incident velocity, indicating the absence of an isotope effect. Figure 2 shows data from this study as well as higher energy results from earlier studies: Ne [19], Si [20], Ar [19], Br [21], Ni [22], Ag [22], Au [22], and U [22]. Over a broad range of ion species and energies (1 keV H to 26 MeV U ) the experimental values of f E fall close to the line representing Eq.…”