TY - JOUR

T1 - Vibrational analysis of the elpasolites Cs2NaAlF6 and Cs2NaGaF6 doped with Cr3+ ions by fluorescence spectroscopy

AU - Da Fonseca, R. J.M.

AU - Sosman, L. P.

AU - Dias Tavares, A.

AU - Bordallo, H. N.

PY - 2000/12/1

Y1 - 2000/12/1

N2 - 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 2E and 4T2 excited states of the [CrF6]3- ion are displaced along the eg and a1g and probably the t2g coordinates.

AB - 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 2E and 4T2 excited states of the [CrF6]3- ion are displaced along the eg and a1g and probably the t2g coordinates.

UR - http://www.scopus.com/inward/record.url?scp=0034512573&partnerID=8YFLogxK

U2 - 10.1023/A:1009430530367

DO - 10.1023/A:1009430530367

M3 - Journal article

AN - SCOPUS:0034512573

VL - 10

SP - 375

EP - 381

JO - Journal of Fluorescence

JF - Journal of Fluorescence

SN - 1053-0509

IS - 4

ER -