Velocity distributions of sputtered excited atoms

he properties of atoms sputtered in short-lived electronically excited states from KCl, KI, and LiF single crystal surfaces undergoing energetic Ar;The Doppler profiles were analyzed within the framework of the Thompson-Sigmund theory of velocity distribution. Line profiles calculated from the Thompson-Sigmund theory were compared to the experimental Doppler profiles, with care being taken to explicitly incorporate the instrumental broadening in the lineshape analysis. The Thompson-Sigmund profiles do not fit the experimental profiles. Good fits are obtained only when the surface binding energy for the target material is treated as a fitting parameter, thereby, giving a range of surface binding energies that are far removed from the correct physical surface binding energies for the KCl, KI and LiF targets. These findings reveal that the velocity distributions cannot be truly described by the Thompson-Sigmund theory.;The kinetic energies, determined through the linewidths, are generally low and typically less than 40 eV. For excited atoms sputtered in the K I doublet states, the kinetic energies are in the range of 5 to 40 eV. For lithium atoms in the Li I 670.78 nm excited states, the kinetic energies range from 3 to 10 eV, while for those in the Li I 610.36 nm excited state, the measured energies are from 0.7 to 2.8 eV. These energies are typical of the energies normally measured in an overall sputtering process.;Compelling evidence is found that there is substantial cascade repopulation of the short-lived excited states by longer-lived upper excited states. In fact, the transitions measured at points greater than...