4D-4F EMISSION RESONANCES IN LASER-PRODUCED PLASMAS

Using targets containing compounds of the elements cesium through lutetium, the spectra of laser-produced plasmas were investigated in the grazing-incidence region from 40 to 200 A. The spectra are characterized by strong regions of resonance-like emission extending typically over 9-18 eV. With increasing Z, the spectra show certin systematic variations in character and move monotonically toward shorter wavelengths. From a collisional-radiative plasma model, the ion stages responsible for the emission are identified as VIII through XVI. The resonances are attributed to 4d-4f transitions that tend to overlap for different ion stages of the same element.