ISSN:
1573-4994
Keywords:
Insulators
;
crystal and ligand fields
;
elpasolite
;
chromium
;
time-resolved optical spectroscopy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Interest in 3d transition metal impurities in ionic crystals has increased due to their important role in the laser activity of these materials. Moreover, recent advances in tunable solid-state lasers and high-power semiconductor laser diode arrays have generated a strong interest in investigating new compounds that emit in the visible and near-infrared spectral regions. In particular, many optical studies have been devoted to Cr3+-doped fluoride crystals as a consequence of the high quality of some Cr3+-based laser materials. In the present investigation, the low-temperature emission spectra of Cr3+ ions in the hexagonal elpasolites Cs2NaAlF6 and Cs2NaGaF6 have been measured. Each compound has two crystallographically inequivalent octahedral sites for the Al3+ and Ga3+ ions that can be occupied by Cr3+ ions. For both materials, the luminescence spectrum presents two zero-phonon lines accompanied by a well-defined vibrational structure. The different peaks of the emission broad band are described in terms of phonons of the lattice and normal modes of the octahedral complex [CrF6]3−. A detailed analysis of the vibrational structure observed leads to the conclusion that the 2 E and 4 T 2 excited states of the [CrF6]3− ion are displaced along the e g and a 1g and probably the t 2g coordinates.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009430530367
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