On the spectrum of 168Er

The observed spectrum of 168Er is analyzed within the general framework applicable to deformed nuclei with rotational spectra. The evidence implies a major anharmonicity in the γ vibrational motion. These results are found to be in rather serious disagreement with a recent interpretation of the spectrum based on the interacting boson model. The general structure of the spectrum implied by this model for deformed nuclei is discussed in an appendix. A postscript discusses a major inconsistency in the energy scale employed in the boson analysis. (Auth.)