High-Resolution Visible Laser Spectroscopy of Cobalt Monochloride

The electronic spectrum of cobalt monochloride has been investigated from 415 to 725 nm using a laser-ablation/molecular-beam laser-induced fluorescence spectrometer. Two separate electronic systems with origins near 483.3 and 470.3 nm were observed. Data have been recorded for these two transitions at both low and high resolution. These transitions are now characterized as the [20.7]³Φ₄−X³Φ₄ and [21.3]³Φ₄−X³Φ₄ transitions. A low-resolution vibrational analysis and a high-resolution rotational analysis have been carried out for each system, resulting in accurate values for the ground and excited state vibrational spacings and effective rotational constants. In addition, the magnetic hyperfine structure resulting from the spin of the Co nucleus was resolved and the hyperfine constants were determined. Comparison of the CoCl spectrum with that of CoH and CoF has allowed the ground state electron configuration of (core)(10σ)²(4π)⁴(1δ)³(5π)³(11σ)² to be determined. The hyperfine constants support the electron promotion 11σ→12σ for the observed transitions.