K-shell hole production by light ions in the regionη12≲1

An accurate numerical calculation of $K$-shell hole production by light ions is presented for nonrelativistic target atoms in the projectile energy region ${\eta }^{\frac{1}{2}} (=\frac{\hslash v}{Z_n{e}^2})\lesssim 1$. Both hydrogenic and Hartree-Fock targetatom potentials were investigated. After correcting a computer error in some of our initial results published recently, good agreement is found for proton impact absolute cross sections and for the projectile atomicnumber dependence of the cross section. We also present simple analytical formulas which fairly well reproduce our results for target atomic numbers ranging from $Z_n=13\mathrm{} \mathrm{to} 30$. This will hopefully facilitate the use by experimentalists of this rather involved calculation, which includes up to 54 basis functions. An interesting result of the comparison between the calculated and experimental atomic-number dependence of the cross section is that it suggests charge-transfer contributions to $K$-shell hole production are at least as large as given by the Brinkman-Kramers (BK) approximation. This requires that a great deal of electron stripping occurs as the projectile tries to leave the atom with its captured electron, because experimentally measured cross sections for charge transfer are considerably less than the BK. A simple model is presented which shows that this is to be expected.