The Fano-Lichten model is known to be in good accord with available inner-shell excitation data on gaseous targets, whereas there exist several examples of discrepancies between the model and results of solid-target experiments. As will be discussed in detail in this paper, these apparent discrepancies may be explained by so-called "solid effects." An equation taking due account of energy-loss straggling, x-ray generation in recoil collisions, and targets absorption of emitted x rays is used to relate the measured x-ray yield to an x-ray production cross section averaged over the equilibrium distribution of projectile charge states in the solid. Experimental cross sections are reported for the Al $K$ x-ray production in Al targets bombarded with N, Al, and Ar ions, and for the Ne $K$ x-ray production of Ne projectiles incident on Mg, Al, Si, and P targets. The neglect of solid effects in published x-ray data is commented upon.

• Received 2 April 1973

DOI:https://doi.org/10.1103/PhysRevA.8.1814