HYPERFINE AND SPIN-ORBIT STRUCTURE OF THE (4)DELTA(I) GROUND-STATE OF COO

A detailed examination of the structure of the 4DELTA(i) ground state of gaseous CoO has been carried out from analysis of the electronic spectrum near 6300 angstrom, using intracavity dye laser and wavelength-resolved fluorescence methods. The intracavity experiments have given the details of the hyperfine structure of the two lowest spin-orbit components at sub-Doppler resolution, permitting the hyperfine parameters, a = 0.0229(5) cm-1 and (b+c) = -0.0111(7) cm-1, to be derived; from the negative value of the contact interaction the electron configuration is established as (4ssigma)2 (3ddelta)3(3dpi)2. The wavelength-resolved fluorescence experiments have given the relative positions of the four spin-orbit components of the X 4DELTA(i) state to +/- 0.3 cm-1. Based on these measurements, a pair of subbands sharing a common electronic upper level, but with the OMEGA = 5/2 and 7/2 components of the ground state as lower levels, has been recognized. Rotational analysis of Doppler-limited intracavity spectra of these two subbands has given an accurate value for the OMEGA = 5/2-7/2 separation as 304.321 +/- 0.007 cm-1.