Crystal-field split energy levels for the
5 
and
5 
ground configuration of Pm
3+in LiYF
4and radiative transition probabilities between these levels were calculated. An electric dipole φ-transition dominates and suggests a CW Pm
3+laser is possible unless Pm
3+-Sm
3+-Nd
3+energy transfer quenches the Pm
5+flurorescence. This dominating transition is from the
5 
at 12444 cm
-1to an
5 
at 1786 cm
-1