We report the results of 4d core-level photoemission spectra for thulium monochalcogenides, TmX (X = S, Se, Te) around the 3d-4f absorption edge. The resonance effect for Tm 4d emission occurs through partial decay channels of the 3d-4f excited states. The lifetime-broadening phenomenon, which depends strongly on the binding energy, is also employed here for elucidation of 4d photoelectron spectral features. The behavior of a particular decay channel, referred to as 3d-4d4f, followed by preferential excited states was studied extensively. (C) 1998 Elsevier Science B.V.