Energy-Level Scheme for Nd3+ in CaWO4

Abstract

The free ion parameters obtained from a least‐squares fit to the six lowest free ion levels of Nd³⁺ in CaWO₄, neglecting configuration mixing, are (in cm⁻¹): $E^1\text{\hspace{0.17em}=\hspace{0.17em}4859.7}$ , $E^2\text{\hspace{0.17em}=\hspace{0.17em}24.78}$ , $E^3\text{\hspace{0.17em}=\hspace{0.17em}482.0}$ , and $\text{ζ\hspace{0.17em}=\hspace{0.17em}873.8}$ . The rms deviation of this fit was 21. Crystal‐field parameters appropriate to $S_4$ symmetry were fit to the structure of the ${}^4{I}_{\text{9/2}}$ and ${}^4{I}_{\text{11/2}}$ levels. Intermediate coupling wavefunctions obtained from the free ion fit were used. $\mathrm{J-J}$ mixing between the ${}^4{I}_{\text{9/2}}$ and ${}^4{I}_{\text{11/2}}$ states was considered. The crystal‐field parameter values found are (in cm⁻¹): $B_0^2\text{\hspace{0.17em}=\hspace{0.17em}514.2}$ , $B_0^4\text{\hspace{0.17em}=\hspace{0.17em}−1040.0}$ , $B_0^6\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}60.0}$ , $B_4^4\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}1071.6}$ , $B_4^6\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}980.0}$ , $B_4^{\text{′4}}\text{\hspace{0.17em}=\hspace{0.17em}16.4}$ , and $B_4^{\text{′6}}\text{\hspace{0.17em}=\hspace{0.17em}13.1}$ . The rms deviation of this fit was 9.5. We calculate the ground‐state $g$ values to be $g_{\Vert }\text{\hspace{0.17em}=\hspace{0.17em}1.633}$ and $g_{\perp }\text{\hspace{0.17em}=\hspace{0.17em}2.621}$ . The corresponding experimental values are 2.035 and 2.537. By changing the $B_m^n$ we can get a better g‐value fit, namely, 2.025 and 2.593.