RESONANT PHOTOEMISSION SPECTRA AT THE 4F AND 5P LEVELS OF TM ACROSS THE 4D-4F ABSORPTION THRESHOLD

The decay of the 4d core hole in the rare-earth metal thulium, followi ng resonant absorption into the 4f level, has been monitored by photoe lectron spectroscopy and compared with calculations predicting the 4f and 5p electron distribution curves. The Tm, deposited on a cooled Ag surface to stabilize both trivalent and divaient states, shows three s trong peaks in the total electron yield spectrum. The first absorption peak (H-3(6)) results in a resonant enhancement of predominantly the 5s and 5p emission, together with an increase in the trivalent 4f emis sion. The weaker absorption peak (H-3(5)) leads to a relatively small increase in the emission through the trivalent 4f state. The last abso rption peak ((3)G(5)) shows a strong enhancement of two specific chann els, at higher binding energy, within the trivalent 4f emission. The d ivalent 4f emission is only enhanced near the H-3(6) resonance.