Sub‐Doppler Zeeman spectroscopy of the CeO molecule

Sub‐Doppler Zeeman spectra of several low‐J rotational lines in 0–0 bands of CeO[16.5]2–X12, [16.5]4–X23, [18.4]4–X34, and [19.3]3–X43 systems have been recorded by intermodulated fluorescence spectroscopy. Electronic g values for the four lower states [the Ω=Ja states of the Ce+2(4 f 6s)O−2] superconfiguration obtained from Zeeman splittings of low‐J lines at magnetic fields up to 1100 G, are found to agree with g values calculated from the eigenvectors of a ligand field effective Hamiltonian. The present results demonstrate the capability of the ligand field model to predict electronic properties in addition to energies and illustrate the value of the Zeeman effect for uncovering the atomic–ion quantum numbers which are not normally specified for molecules in the strong spin‐orbit [Hund’s case (c)] limit.