Comments on the physical significance of E1 values for excited sputtered atoms

Measurements of parameters associated with the emitted photons from a number of elements have indicated that the kinetic energies of sputtered excited atoms may be of the order of 10²–10³ eV. A recent result of Yu et al. [Phys. Rev. Letters 48 (1982) 427] is in contradiction to those results. We argue that the high energy values reported are the result of cascade repopulation of the upper level of the observed transition, distorting the experimental observations. Cascade corrections could reduce the energy values to the order of 10 eV, similar to the most probable energy of secondary ions.