Predissociation in the B0+ State of YbS and a Combined Isotopomer Fit to the X0+ State Potential Energy Curve

High-Resolution Laser Spectroscopy of CaS: Deperturbation Analysis of the AΣ+−X1Σ+ Transition

“…The alkaline-earth monosulfides CaS, SrS, and BaS have been the subject of a number of spectroscopic investigations. − However, their electronic structures, and more specifically, their low-lying electronic states, are not as well characterized as those of the alkaline-earth monoxides. − With the exception of CaS, all of the known low-lying excited states of the alkaline earth monoxides and monosulfides are extensively perturbed. Our interest in perturbations observed recently in YbS − spurred the present reinvestigation of the A 1 Σ + −X 1 Σ + electronic transition in CaS.…”

Laser spectroscopy of holmium monosulphide: Electronic, vibrational and rotational structure of the A[14.79]8.5–X8.5, A[14.79]8.5–W[0.25]7.5 and A[14.79]8.5–V[0.98]7.5 transitions

“…Because of the effective shielding properties of the 4f orbitals, the vibration frequency is expected to be similar for all the lanthanide sulphide states with similar configurations, in this case f N s. For the oxides, we found that HoO, with a ground f 10 s configuration has a vibration frequency of $830 cm À1 [2] whereas that of YbO, with a closed shell f 14 configuration was $690 cm À1 [3]. For YbS, also with a f 14 ground configuration, the vibration frequency is $365 cm À1 [7]. If we assume that the ratio of the vibration frequencies for the two configurations is similar for the sulphides and oxides, then we would expect a vibration frequency of $440 cm À1 for HoS, which is close to the observed value.…”

“…The properties of the molecules are found to mirror very well those of the metal atom ion in which the states of the ion are perturbed by the axial field of the oxygen or halogen ligand. Of the lanthanide sulphides, which would be expected to have electronic structure similar to that of the oxides, only YbS [6,7] has been observed to date. We report here the first results on the spectroscopy of Holmium monosulphide (HoS).…”