Fluorescence ( ${}^{4}T_{2} \to {}^{4}A_{2}$ ) and phosphorescence ( ${}^{2}E \to {}^{4}A_{2}$ ) in MgO: ${Cr}^{3 +}$

15 January 1975

journal article
research article
Published by American Physical Society (APS) in Physical Review B

Vol. 11 (2) , 920-928
https://doi.org/10.1103/physrevb.11.920

Abstract

Steady-state and time-resolved spectra have been recorded for MgO:

{Cr}^{3 +}

crystals as a function of temperature, excitation wavelength, and

{Cr}^{3 +}

concentration. The spectra and lifetimes for emission from the various centers have been determined. Both prompt and delayed broad-band fluorescence are emitted, but only delayed fluorescence is associated with the cubic and tetragonal sites. The thermal quenching mechanism of the

R

-line lifetime is reconsidered and shown to involve repopulation of the

{}^{4}T_{2}

state. For the cubic and tetragonal centers

{}^{4}T_{2}

is above

{}^{2}E

, the

{}^{4}T_{2}

lifetime < 0.5 nsec and the

{}^{4}T_{2} \to {}^{2}E

intersystem crossing efficiency is unity. For the rhomhic centers, where

{}^{4}T_{2}

is below

{}^{2}E

, the

{}^{4}T_{2}

lifetime is 35 μsec. The total luminescence quantum yields for all centers is close to unity.

Keywords

This publication has 11 references indexed in Scilit:

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Fluorescence (T24→A24) and phosphorescence (E2→A24) in MgO:Cr3+

Abstract

Keywords

Fluorescence ( ${}^{4}T_{2} \to {}^{4}A_{2}$ ) and phosphorescence ( ${}^{2}E \to {}^{4}A_{2}$ ) in MgO: ${Cr}^{3 +}$