Abstract

Measurements of isotope ratios by resonance ionization mass spectrometry depend critically on knowledge of isotopic-specific effects in the laser excitation-ionization process. Reports of odd-even isotope selectivity in RIMS studies of Mo, Sn,¹ and Ti have led us to investigate isotope shifts in a RIMS study of Os. We identify three sources of laser-induced mass selectivity: (i) wavelength and bandwidth effects, (ii) selection rule and polarization effects, and (iii) dynamic effects.² (i) In the presence of optical isotope shifts and hyperfine structure the finite laser bandwidth and reproducibility of wavelength setting produce isotope shifts as a result of the incomplete overlap of the laser spectrum with the absorption maxima of the Os isotopes and their HFS components.

© 1991 Optical Society of America