Laser excitation of ionic fluorescence overcomes the problem of spectral interferences encountered when trace analysis of the rare earths is performed by atomic/ionic emission spectrometry in the inductively coupled plasma. Two pulsed, excimer pumped, tunable dye lasers are used to excite ionic fluorescence of rare earths in an inductively coupled plasma. Since several fluorescence lines have been observed after laser excitation, it is possible to draw partial energy level diagrams for lanthanum, ytterbium, europium, and lutetium. Detection limits, linear dynamic ranges, and sensitivities are also reported. This is the first time that two-step excited fluorescence has been observed for any rare earths in an inductively coupled plasma.
M. E. Tremblay, J. B. Simeonsson, B. W. Smith, and J. D. Winefordner, "Laser-Induced Double Resonance Ionic Fluorescence of Rare Earths in the Inductively Coupled Plasma," Appl. Spectrosc. 42, 281-285 (1988)