THE PREDICTED INFLUENCE OF RELATIVISTIC EFFECTS ON THE KL1L2(P-3(0)) AUGER TRANSITION INTENSITY OF THULIUM PROVED

The KLL Auger spectrum of thulium from Yb-169 decay has been analysed at an instrumental resolution of 13 eV using a combined electrostatic spectrometer, Energies and relative intensities of the individual KLL transitions have been determined and compared with calculations, A rel iable value of 0.67(5) for the KL1L2(P-3(0))/(P-1(1)) transition inten sity ratio obtained from our partly resolved KL1L2 doublet proved, for the first time, a sharp increase of the KL1L2(P-3(0)) intensity in th e high Z region due to the relativistic effects predicted by relativis tic calculations in intermediate coupling with configuration interacti on. For the first time, a broadening of the KLL Auger lines, probably due to the two different excitation ways of the Tm-169 atoms in Yb-169 decay (K-internal conversion and K-electron capture), has been observ ed, A value of 19.5(8) eV was obtained for the energy separation of th e two thulium KLL Auger spectra shifted to each other, arising from th e individual excitation modes,and that of 0.81(9) for their intensity ratio ('K-conversion' to 'K-capture'). (C) 1997 Elsevier Science B.V.