The chemistry of the light rare-earth elements as determined by electron energy loss spectroscopy

The energy loss spectra of the rare earths are characterized by sharp M4,5 edges, the relative intensities of which are characteristic of the 4f-shell occupancy of the excited ion. For the light rare earths, the dependence of these relative peak heights on 4f-shell occupancy is quite pronounced. Thus they may be used to determine the oxidation state of the multivalent elements Ce and Pr. The second derivative of the spectrum is shown to be extremely sensitive to the chemical environment. Modern instrumentation and detection techniques allow the oxidation state of Ce and Pr to be determined even when they are present as only minor constituents.