Origin of X-ray photon stimulated desorption of Cl+ and Cl2+ ions from Cl/Si(1 1 1)-(1×1)

In this paper we investigate minority adsorption sites on Cl/Si(1 1 1)-(1×1) with the X-ray standing wave technique. By a combination with X-ray photon stimulated desorption, we show that the coordinates of the desorption-active chlorine minority adsorption site can be determined analytically if standing wave difference spectra are recorded at the chlorine 1s absorption edge. Furthermore, the direct and indirect contributions to the total Cl+ and Cl2+ ion desorption yields above the chlorine K edge can be separated and the ratio of the atomic desorption cross-sections can be estimated.