SPECTROSCOPY AND CRYSTAL-FIELD ANALYSIS FOR ND(3+) IN GDLIF(4)

Spectroscopic results are presented and crystal-field parameters are determined for Nd3+ in the new laser crystal GdLiF4. We take the unusual approach of expanding the crystal field in terms of operators transforming as irreducible representations of the T(d) group. This allows us to directly interpret the parameters in terms of a point-charge structural model. The traditional B(kq) parameters are then obtained via a linear transformation. Their values are nearly identical to those for Nd3+ in YLiF4. The slightly weaker crystal field for GdLiF4 suggests a dilation of the lattice caused by the larger ionic size of Gd3+ as compared to Y3+.