High resolution laser induced fluorescence spectroscopy of the [18.8] (3)Phi(i)-X (3)Phi(i) (0,0) band of cobalt monofluoride

The fine and hyperfine interaction parameters in the [18.8] (3)Phi (upsilon=0) and X (3)Phi (upsilon=0) states of cobalt monofluoride, CoF, have been determined from an analysis of high-resolution laser induced fluorescence spectra of the [18.8] (3)Phi(3)-X (3)Phi(3) and [18.8] (3)Phi(4)-X (3)Phi(4) band systems. The previously reported pure rotational transitions of the X (3)Phi(4)(upsilon=0) state [T. Okabayashi and M. Tanimoto, J. Mol. Spectrosc. 221, 149 (2003)] were included in the data set. The hyperfine parameters for Co-59 (I=7/2) and F-19 (I=1/2) have been interpreted using atomic data together with a proposed molecular orbital description for the [18.8](3)Phi(i) and X (3)Phi(i) states. A comparison of the hyperfine parameters in the X (3)Phi state of cobalt monohydride, CoH, with those of the X (3)Phi state of CoF reveals that the bonding in the two molecules is significantly different. It is shown that, in a situation where the Omega substates of a multiplet degenerate electronic state are analyzed separately, the Fermi contact parameter b can be determined with fair accuracy from the apparent centrifugal distortion of the hyperfine structure. (c) 2006 American Institute of Physics.