Determination of L-Subshell Coster-Kronig Yields of Lanthanum and Praseodymium, Erbium and Hafnium by Synchrotron Photoionization

R.A. BARREA; C. A. PÉREZ; H. J. SÁNCHEZ

Campinas, Brasil

Congreso; RAU 12; 2002

Laboratorio Nacional de Luz Sincrotrón

The radiationless transfer of vacancies among atomic subshells with the same principal quantumnumber constitutes a peculiar class of Auger processes named after its discoverers, Coster andKronigi. Coster-Kronig transitions are of relevance both in fundamental atomic physics and inexperimental applicationsii. Quantitative analytical work requires accurate knowledge of CosterKronig yields, since the transitions redistribute vacancies within one shell, and thus directlyaffect the intensity of emission lines. Furthermore, experimental values of Coster-Kronig yieldsare scarce and difficult to obtain.In this work we present results of the La, Pr, Er and Hf L-subshells Coster-Kronig yieldsmeasured by a selective photoionization of individual L-subshells with a monochromatized xraybeam of synchrotron radiation. The measurements were carried out at the XRF beamline ofthe LNLS. The energy range was chosen in order to cover the whole L-energies absorptionedges. Several energy scans were done, collecting the L fluorescence emitted by the sampleswith a Si(Li) detector. Normalization of the fluorescence intensity to the varying primaryintensity were performed by measuring the Ni K line. The Coster-Kronig yields were derived byfitting the experimental data to the theoretical model.Some comments and discussions about the obtained results will be presented.