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https://hdl.handle.net/10442/19319
Εξειδίκευση τύπου : | Άρθρο σε επιστημονικό περιοδικό |
Τίτλος: | Unusually high oxidation states of manganese in high optical basicity silicate glasses |
Δημιουργός/Συγγραφέας: | Ashjari, Amir Topper, Brian Hess, Lars H. Greiner, Lucas Tolliver, Jared Cormack, Fiona [EL] Παλλές, Δημήτρης[EN] Palles, Dimitris [EL] Καμίτσος, Ευστράτιος Ι.[EN] Kamitsos, Efstratios I. Brik, Mikhail G. Möncke, Doris |
Ημερομηνία: | 2024 |
Γλώσσα: | Αγγλικά |
ISSN: | 25901478 |
DOI: | 10.1016/j.omx.2024.100371 |
Περίληψη: | Unusually high oxidation states of manganese were stabilized within a cesium-barium silicate (CBS) glass system of extremely high optical basicity. The highest basicity was obtained for the metasilicate glass 40Cs2O–10BaO–50SiO2 (mol%) with an optical basicity of
= 0.81. The presence of Mn5+ (d2) as well as Mn6+ (d1) is confirmed by UV–Vis, photoluminescence, and Raman spectroscopy. The UV–Vis spectrum is dominated by the Mn3+ (d4) absorption at 526 nm for low-basicity glasses, which is replaced by a peak at 679 nm (Mn5+) and, finally, a band at 603 nm (Mn6+) in the glass with the highest basicity (
= 0.81). In this glass, the Mn5+/Mn6+ ratio varies with the melting conditions. Photoluminescence (PL) spectroscopy under 633 nm excitation confirms the presence of Mn5+, showing the narrow, forbidden 1E
3A2 transition located at 1191 nm with vibrational sidebands at 1245 nm and 1290 nm. The measured static fluorescence intensity due to Mn5+ grows exponentially with increasing optical basicity. The near infrared fluorescence decay was bi-exponential, with time constants of 14 and 51 μs. The absence of Mn4+ in CBS glasses was confirmed by PL and electron paramagnetic resonance (EPR) spectroscopy. Despite initial doping as MnO2, metastable Mn4+ disproportionates into lower and higher valent manganese species, followed by reduction or oxidation of manganese to a stable species as ruled by the basicity of the glass and oxygen availability during melting. A structural study of the glasses by Raman spectroscopy revealed a resonance enhancement effect for the symmetric stretching mode of MnO4-tetrahedra at ∼800 cm−1 with overtones observed at higher frequencies. |
Τίτλος πηγής δημοσίευσης: | Optical Materials: X |
Τόμος/Κεφάλαιο: | 24 |
Θεματική Κατηγορία: | [EL] Φασματοσκοπία[EN] Spectroscopy [EL] Ανόργανη χημεία[EN] Inorganic chemistry |
Λέξεις-Κλειδιά: | cesium-barium metasilicate hgh optical basicity resonance Raman enhancement Mn5+ Mn6+ redox equilibria optical spectroscopy |
EU Grant identifier: | DMR-1626164 |
Κάτοχος πνευματικών δικαιωμάτων: | © 2024 The Authors. Published by Elsevier B.V. |
Όροι και προϋποθέσεις δικαιωμάτων: | This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/). |
Ηλεκτρονική διεύθυνση στον εκδότη (link): | https://doi.org/10.1016/j.omx.2024.100371 |
Εμφανίζεται στις συλλογές: | Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο
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