Fluorine K Auger spectra were measured for a series of alkali-metal and alkaline-earth fluorides excited by Al Ka x rays. A new line was observed in some Auger spectra, and the highest intensity of this line was found for KF. The energy and intensity variations of this line depending on the metal ion are explained by a resonant electron-transfer relaxation mechanism following the Auger transition.PACS numbers: 32.80.HdIt is well established that the energy of Auger electrons emitted from atoms bound in solids is higher than that of Auger electrons emitted from free atoms. 1 The main cause of this energy shift is extra-atomic relaxation of the environment screening the created double-hole final state. For metals, where conduction electrons are most effectively screening the holes, this shift is largest, about 10-15 eV. 1 For ionic solids this relaxation shift due to polarization is much smaller. 2 Other relaxation mechanisms are not yet reported. Recent measurements 3 of the relative intensity of the first KL\ satellite line in fluorine K x-ray spectra of ionic fluorine compounds gave evidence for a resonant electron-transfer (RET) mechanism following Islp double ionization of the fluorine ion. The final state after Auger-electron emission by a fluorine ion is also a double-hole state. When this RET is now interpreted as a special relaxation mechanism of the ionic crystal in response to the created double hole, RET might also be seen in AT-Auger-electron spectra of ionic fluorine compounds if this RET relaxation process is fast enough to affect the emitted Auger electrons. Measuring x-ray spectra and the most intense Auger line of fluorine for a series of fluorine compounds, FIG. 1. Fluorine K Auger spectra induced by Al Ka x rays. The position of the Mline is indicated by arrows. The energy is given with respect to the Fermi level of the spectrometer.Deconninck and Van Den Broek 4 found some irregularities in the Auger spectra of KF, SrF 2 , and BaF 2 which may indicate the influence of RET, but they could not give an explanation for these irregularities.In this Letter we report the results of a systematic investigation of the K Auger spectra of fluorine for the alkali-metal and alkaline-earth fluorides. We shall show that the found anomalous structure of the main line (KL 2 $L 23 )can be explained by a new resonant electron-transfer relaxation mechanism between the outer np level of the metal ion and the 2p level of the fluorine ion.The fluorine K Auger spectra of NaF, KF, RbF, CsF, MgF 2 , CaF 2 , SrF 2 , and BaF 2 were measured with a HP-5050A ESCA spectrometer. Monochromatized Al Ka x rays were used for excitation. The pressure in the analyzer chamber was kept less than 2xl0"" 9 mbar and no contaminations were found during measurements. The fluorine compounds were evaporated on gold-plated stainless-steel backings and brought directly into the analyzer chamber without breaking the vacuum. To avoid charging, the samples were flooded with electrons from an electron gun establishing a single vacuum energy leve...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.