Abstract

The number of organometallic free radicals studied spectroscopically in the gas phase has been very limited until quite recently. Application of Broida oven, laser photolysis and laser photolysis/vaporization techniques to synthesize these transient species has significantly enlarged the number of reports over the past few years. This research group’s contribution to the area have been a series of reports by Robles, Ellis and Miller detailing electronic and vibrational structures (~.5 cm^-1 resolution) of 15 species of the form M-R (M = Mg, Ca, Zn and Cd; R = cyclopentadienyl (Cp), pyrollyl (Py) and methylcyclopentadienyl (MCp)) and M-CH₃ (M = Ca, Zn and Cd), many of them observed for the first time.^1-8 These molecules are more than simply novel constructs. The methyl and Cp derivatives are recognized as important intermediates in metal deposition processes while the metal-Py species are found as subunits in several chemical substances of biological importance. Metal-ligand bonding sites, vibrational frequencies, spin-orbit splittings and barriers to internal rotation are some of the types of information that this work has yielded. To augment this work, a rotationally resolved study is presented here which confirms the electronic state symmetry assignments given in earlier studies, and more importantly, determines rotational constants and other interaction parameters of these radicals.

© 1993 Optical Society of America