Inter- and Intraconfigurational Transitions of Nd3+ in Hexafluoroelpasolite Lattices

Excitation of the 4f3 ion Nd3+ in hexafluoroelpasolite lattices by synchrotron radiation of wavelength ∼185 nm leads to fast 4f25d → 4f3 emission below 52 630 cm-1 and slower 4f3 → 4f3 emission from the luminescent states 4F3/2 Γ8u (11 524 cm-1) and 2G(2)9/2 Γ8u (∼47 500 cm-1). The near-infrared emission is well-resolved, and a clear interpretation of the 4I9/2 crystal field levels and of the one-phonon vibronic sideband is given. The excitation spectrum of the 2G(2)9/2 emission enables clarification of the structure of the 4f25d configuration (which extends from ∼52 000 to 128 000 cm-1). Detailed energy level and intensity calculations have been performed, which provide simulations of the d−f emission and the f−d excitation spectra in good agreement with experiment. It is interesting that although the 4f3 2G(2)9/2 Γ8u → 4f3 4I J transitions are very weak in intensity compared with transitions terminating upon higher multiplet terms, most of the 4f25d (3H) 4I9/2 Γ8g → 4f3 emission intensity resides in the transitions to 4I J .