Optical spectra and crystal field analysis of Nd3+ in the cubic Cs2NaYCl6 host

Publisher Website
Google Scholar
Abstract
Optical absorption and emission measurements are reported for the Cs2NaYCl6:Nd3+ (∼5 mol %) system under variable‐temperature (4.2–296 K) conditions. The absorption measurements span the 12 000–24 000 cm−1 spectral region, and emission spectra are presented throughout the 13 300–18 860 cm−1 region. All the spectra are consistent with the retention of octahedral (Oh) site symmetry for the Nd3+ ions down to 4.2 K. Thirty‐four crystal‐field levels spanning 14 multiplets of the Nd3+ 4f3 electronic configuration are located and assigned on the basis of the experimental data. The most intense lines observed in each of the multiplet‐to‐multiplet transition regions are assigned to one‐phonon (electric‐dipole) vibronic transitions associated with the three odd‐parity moiety modes of the NdCl3−6 cluster, ν3(tlu), ν4(tlu), and ν6(t2u). The ν3 lines generally appear as doublets (split by ∼10–15 cm−1) and are displaced from magnetic‐dipole origins by ∼245–260 cm−1; the ν4 lines are displaced from origins by ∼100 cm−1, and are generally sharp and symmetric; and the ν6 lines are generally asymmetric in shape (or appear as doublets split by ∼2–6 cm−1), and are displaced from origins by 70–75 cm−1. Additional vibronic lines are observed persistently at displacement energies of ∼40–45 and ∼55–60 cm−1, but these lines are considerably less intense than those assigned to the ν3, ν4, and ν6 moiety‐mode vibrations. The energy level data obtained from experiment is rationalized in terms of a 9‐parameter model which includes the radial spin‐orbit interaction parameter (ζso), the Slater–Condon one‐particle electrostatic interaction parameters (F2, F4, and F6), the two‐particle electrostatic configuration‐interaction parameters (α, β, and γ), and the octahedral (Oh) crystal‐field interaction parameters (B(4)0 and B(6)0). The values deduced for the crystal‐field parameters are B(4)0 =2400 cm−1 and B(6)0 =−330 cm−1 (expressed with unit‐tensor normalization).

This publication has 57 references indexed in Scilit: