X ray spectroscopic study of 4f heavy rare earth metals

L absorption spectra of 4f heavy rare earth elements, 65Tb to 69Tm and 71Lu, in the pure metallic state have been investigated with a 40 cm curved mica crystal spectrograph of transmission type. Microphotometer records of L2 and L3 absorption edges taken at 25* magnification exhibit two distinct abrupt rises in absorption (L'2 and L'3 edges) except for 71Lu. Wavelengths of L absorption edges of these metals have been measured. A prominent absorption maximum (or so called 'white line') has been detected at the L2 and L3 edges. Peak position of the white line, its distance from the L edge position and its full width at half maximum have been reported. An attempt has been made to estimate the position of 4f unoccupied levels and to interpret the observed spectral features in the light of available theoretical data on the rare earth metals in question.