The photon-stimulated ion desorption spectra of H + and Cl + ions from variable-coverage CHCl 3 adsorbed on Si(100) at ∼90 K are compared with the Si L 2 3 -edge total electron yield (TEY) and total X-ray-fluorescence yield spectra of Si(100) in the energy range of 97-110 eV. The Si 2p edge jump, both in the H + and Cl + yields, is proportional to that in the TEY of Si(100)). All vanish for the thickest CHCl 3 multilayer, indicating that the observed Si L 2 3 -edge jump in the H + and Cl + yields from CHCl 3 /Si(100) is attributable to an X-ray-induced electron-stimulated desorption (XESD) process. The main Features between the Si L 2 3 -edge TEY spectrum and H + photon-stimulated ion desorption spectrum from solid Si(CH 3 )Cl 3 are similar. This result is interpreted in terms of photodissociation processes which originate from Auger decay of core-excited states as proposed by Knotek and Feibelman. This direct desorption mechanism dominates over desorption stimulated by secondary electrons.