Accession Number : AD0603459

Title :   FLUORESCENCE OF TRANSITION METAL IONS IN CRYSTALS.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR INSULATION RESEARCH

Personal Author(s) : Bartolo,Baldassare Di

Report Date : JUN 1964

Pagination or Media Count : 74

Abstract : Experiments made evaluate the temperature dependence of linewidth, lineshift, and lifetime of the peaked fluorescence presented by Cr(3+) and V(2+) impurities in A12O3 and MgO. Thermal line broadening is due to Raman scattering of phonons, and thermal lineshift to stationary effects of the ion-vibration interaction. The vibronic spectrum associated with the (2)E to (4)A2 fluorescence transition at 8700A of V(2+) in MgO was investigated as a function of temperature. At low temperatures vibrational satellites are observed only on the lowenergy side of the pure electronic transition, corresponding to spontaneous phonon emission, while at higher temperatures they are also on the high-energy side, corresponding to phonon absorption. With increasing temperature the vibronic bands become more intense relative to pure electronic transition, the peaks broaden, and multiphonon processes enter which combine to form a broad fluorescence continuum extending from 7000 to 10,500A. The total intensity of the fluorescence spectrum was measured from 77 to 700K. The fluorescence lifetime of the (2)E level, which is 50 msec and nearly temperature-independent at 77K, decreases rapidly above 200K to 0.03 msec at 800K. (Author)

Descriptors :   (*FLUORESCENCE, ABSORPTION SPECTRA), (*TRANSITION METALS, FLUORESCENCE), (*CRYSTALS, FLUORESCENCE), MAGNESIUM COMPOUNDS, ALUMINUM COMPOUNDS, OXIDES, IMPURITIES, MAGNETIC MATERIALS, IONS, CHROMIUM, VANADIUM, PHONONS, ABSORPTION, SCATTERING, PHOTONS, ATOMIC ENERGY LEVELS, ELECTRON TRANSITIONS, CRYSTAL LATTICES, VIBRATION

Distribution Statement : APPROVED FOR PUBLIC RELEASE