Εξειδίκευση τύπου :	Ανακοίνωση σε συνέδριο
Τίτλος:	Spectroscopic study of manganese-containing borate and borosilicate glasses: Cluster formation and phase separation
Δημιουργός/Συγγραφέας:	Möncke D. Ehrt D. [EL] Καμίτσος, Ευστράτιος Ι.[EN] Kamitsos, Efstratios I.
Ημερομηνία:	2013
Γλώσσα:	Αγγλικά
ISSN:	0031-9090
Περίληψη:	The coordination and bonding of Mn2+ ions in glasses can be probed sensitively and selectively by electron paramagnetic resonance (EPR) and photoluminescence spectroscopy. These methods also give information on Mn-Mn ion interactions and cluster formation. Mn2+ ions were found to be tetrahedrally coordinated in borosilicate glasses of high optical basicity, and octahedrally coordinated in low alkaline borosilicate glasses (Duran-type) as well as in binary borate glasses. Broad emission bands and multicomponent fluorescence decay curves in Duran glasses indicate very strong Mn-Mn ion interactions and the presence of multiple Mn2+ sites, even at low Mn-levels. The EPR spectra show exchange narrowing with increasing Mn content in the Duran series, which is caused by a decrease in the Mn-Mn distances as edge sharing MnO6 octahedra are formed. The network structure of Mn-containing binary and ternary borate glasses is discussed on the basis of their infrared spectra. Addition of MnO to Duran glasses is found to cause the preferential transformation of [BO3]0 to [BO 4]- groups, and to a lesser extent of silicate Q 4 to Q3 units. An increase of the relative population of homopolar B-O-B or Si-O-Si bonds, with the simultaneous decrease in the number of mixed B-O-Si bonds, is also observed, and this explains the visible phase separation of Duran glasses when MnO is added in excess of 4 mol%.
Τίτλος πηγής δημοσίευσης:	Physics and Chemistry of Glasses: European Journal of Glass Science and Technology Part B
Τόμος/Κεφάλαιο:	54
Τεύχος:	1
Σελίδες:	42-51
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry [EL] Φασματοσκοπία[EN] Spectroscopy
Αξιολόγηση από ομότιμους (peer reviewed):	Ναι
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο