Projectile-charge-state dependence of target $L$-shell ionization by 1.86-MeV/amu fluorine and silicon ions and 1.8-MeV/amu chlorine ions

$L\alpha$ x-ray-production cross sections have been measured for solid targets of ${}_{60}{}^{}{}_{}{}^{}\mathrm{Nd}$, ${}_{67}{}^{}{}_{}{}^{}\mathrm{Ho}$, and ${}_{79}{}^{}{}_{}{}^{}\mathrm{Au}$ for 1.86-MeV/amu ${}_9{}^{19}{}_{}{}^{}\mathrm{F}$ and ${}_{14}{}^{28}{}_{}{}^{}\mathrm{Si}$, and 1.8-MeV/amu ${}_{17}{}^{35}{}_{}{}^{}\mathrm{Cl}$ ions as a function of the incident charge state. From the projectile-charge-state dependence of the cross sections, both direct-ionization and electron-capture contributions were extracted for a comparison to Coulomb ionization theories. The data provide supporting evidence for the theory of electron capture with a reduced binding effect. With standard fluorescence and Coster-Kronig yields uncorrected for multiple-ionization effects, the direct ionization theories did not simultaneously reproduce the projectile-$Z_1$ and target-$Z_2$ dependences of the data.