Abstract

The most insightful molecular information comes from the analysis of optical spectra recorded at a resolution sufficient to resolve splittings associated with the fine interactions (rotational, spin–rotation, etc.), hyperfine interactions (Fermi contact, quadrupole, etc.), and the application of external fields (Stark and Zeeman). In the case of freely rotating metal containing polyatomic molecules this requires the combination of a “cold” molecular beam sample preparation, spectral resolution of cw-dye laser excitation, and the sensitivity of laser induced fluorescence. A review of our application of these approaches to diatomic and polyatomic metal containing compounds will be given. A comparison of the applicability of conventional effusive ovens to produce “hot” molecular beams, with laser ablation/reactant and “pickup” methods used to generate “cold” beams will be made. The spectroscopic techniques described include optical Stark LIF and microwave-optical double resonance using the pump/probe detection scheme (MODR-P/P). The MODR-P/P is particularly useful in complex molecular systems because it exploits the sensitivity of LIF detection, while probing only the ground electronic state. We have demonstrated that this technique is compatible with the laser ablation/reactant scheme. The molecular systems to be considered are transition metal oxides and the alakaline earth monocynides.

© 1992 Optical Society of America