SELECTIVE ISOTOPE DETERMINATION OF LANTHANUM BY DIODE-LASER-INITIATEDRESONANCE-IONIZATION MASS-SPECTROMETRY

A diode-laser step has been incorporated into a resonance-ionization m ass spectrometry optical excitation process to enhance the isotopic se lectivity of the technique. Lanthanum isotope ratio enhancements as hi gh as 10(3) were achieved by use of a single-frequency cw diode laser tuned to excite the first step of a three-step excitation-ionization o ptical process; the subsequent steps were excited by use of a pulsed d ye laser. Applying the same optical technique, we measured atomic hype rfine constants for the high-lying even-parity D-4(5/2) State of lanth anum at 30 354 cm(-1) The general utility of this spectral approach is discussed.