Optical spectroscopy of Mn2+ ions in solid solution and Suzuki phase in NaCl single crystals

Abstract

The optical spectroscopy of Mn'+ ions both in dipolar form and forming Suzuki-phase precipitates has been studied in NaCl by photostimulated luminescence at room and liquid nitrogen temperatures. An analysis of the positions of the crystal field transitions shows that the 10 Dq value is slightly higher (about 7%) in the Suzuki than in the dipolar phase while the covalency is the same in both cases. Such analysis allows us to estimate the value I" -/~ = 4.8% from the optical data which is in agreement with the EPR data for [Mnel,]' -clusters. Moreover, an intense band peaking at 231 nm which disappears when the dipolar phase is formed has been ascertained to be associated with the Suzuki phase. This band has been assigned to the double excitation 'A ItS) + 'A ItS) -> 'T,(G) + [4A ,(G). 4E(G)]; that is consistent with the existence of Mn'+ ions in close positions in the Suzuki phase.

Transition metal and rare earth quad-doped photovoltaic phosphate glasses toward raising a-SiC:H solar cell performance

“…Transition metal (TM) ion-doped materials can emit broadband spectra in the visible light range [8,9], and the prices of TM materials are usually lower than those of RE materials. Meanwhile, phosphate glasses have many merits, such as low cost, good thermal and chemical stability, high concentration of luminous ions, large emission and absorption cross-sections (CS), and high transparency for the 560∼680 nm optimum wavelength of a-SiC:H materials [10,11].…”

Estudo comparativo entre as propriedades dos centros luminescentes e paramagnéticos da antigorita e da lizardita do grupo da SERPENTINA: `Mg IND.3´[Si IND.2´`O IND.5´]`(OH) IND.4´

“…No espectro da lizardita observamos uma banda numa região inferior a 500 nm que não aparece na antigorita conforme mostra a A diferença mais significativa é observada para comprimentos de onda menores a 450 nm. Podemos observar na lizardita (Figura 5-46), um conjunto de sinais que não são observados na antigorita (Figura 5-44); estas bandas podem ser identificadas como sendo de Mn 2+ (Rodriguez et al, 1993) e Fe 3+ (Marfunin, 1979…”