Electronic Energy Levels and Crystal Quantum States of Tm (IV)

To date limited agreement has been obtained between theory and experiment for 4f→4f transitions for Tm (IV) (4f12). It is clear from the considerations that have appeared so far in the literature that intermediate coupling is important in the case of Tm (IV). Solutions of the intermediate field equations yield ζ4f=2700 cm—1, F2=450 cm—1, and x=(ζ/F2)=3. Experimental agreement to ±200 cm—1 was obtained.