Benvenuti nell'Anagrafe della Ricerca d'Ateneo
La valutazione delle attività di ricerca che si svolgono nelle università ha assunto un'importanza rilevante sia per l'intero sistema universitario sia all'interno di ogni singolo ateneo. Roma Tre si è quindi dotata di idonei strumenti informativi in grado di supportare al meglio le azioni di monitoraggio e di valutazione delle attività di ricerca svolte nei propri dipartimentied ha realizzato una Anagrafe della Ricerca di Ateneo.
EnglishWe report here a single-crystal polarized-light study of stoppaniite, ideally (Fe,Al,Mg)4(Be6Si12O36)(H2O)2(Na,[]), from Capranica (Viterbo). Polarized-light FTIR spectra were collected on an oriented (hk0) section, doubly polished to 15 μm. The spectrum shows two main bands at 3,660 and 3,595 cm-1; the former is strongly polarized for E normal c, while the latter is polarized for E //c. A sharp and very intense band at 1,620 cm-1, plus minor features at 4,000 and 3,228 cm-1 are also polarized for E //c. On the basis of literature data and considering the pleochroic behavior of the absorptions, the 3,660 cm-1 band is assigned to the ν3 stretching mode and the 1,620 cm-1 (associated with an overtone 2*ν2 at 3,230 cm-1) band to the ν2 bending mode of “type II” water molecules within the structural channels of the studied beryl. The sharp band at 3,595 cm-1 is not associated with a corresponding ν2 bending mode; thus it is assigned to the stretching vibration of O–H groups in the sample. The minor 4,000 cm-1 feature can be assigned to the combination of the O–H bond parallel to c with a low-frequency metal-oxygen mode such as the Na–O stretching mode. The present results suggest that the interpretation of the FTIR spectrum of Na-rich beryl needs to be carefully reconsidered.
DELLA VENTURA G, BELLATRECCIA F, & ROSSI P (2007). The single-crystal, polarized-light, FTIR spectrum of stoppaniite, the Fe analogue of beryl. PHYSICS AND CHEMISTRY OF MINERALS, 34, 727-731.
| Titolo: | The single-crystal, polarized-light, FTIR spectrum of stoppaniite, the Fe analogue of beryl | |
| Autori: | ||
| Data di pubblicazione: | 2007 | |
| Rivista: | ||
| Citazione: | DELLA VENTURA G, BELLATRECCIA F, & ROSSI P (2007). The single-crystal, polarized-light, FTIR spectrum of stoppaniite, the Fe analogue of beryl. PHYSICS AND CHEMISTRY OF MINERALS, 34, 727-731. | |
| Abstract: | We report here a single-crystal polarized-light study of stoppaniite, ideally (Fe,Al,Mg)4(Be6Si12O36)(H2O)2(Na,[]), from Capranica (Viterbo). Polarized-light FTIR spectra were collected on an oriented (hk0) section, doubly polished to 15 μm. The spectrum shows two main bands at 3,660 and 3,595 cm-1; the former is strongly polarized for E normal c, while the latter is polarized for E //c. A sharp and very intense band at 1,620 cm-1, plus minor features at 4,000 and 3,228 cm-1 are also polarized for E //c. On the basis of literature data and considering the pleochroic behavior of the absorptions, the 3,660 cm-1 band is assigned to the ν3 stretching mode and the 1,620 cm-1 (associated with an overtone 2*ν2 at 3,230 cm-1) band to the ν2 bending mode of “type II” water molecules within the structural channels of the studied beryl. The sharp band at 3,595 cm-1 is not associated with a corresponding ν2 bending mode; thus it is assigned to the stretching vibration of O–H groups in the sample. The minor 4,000 cm-1 feature can be assigned to the combination of the O–H bond parallel to c with a low-frequency metal-oxygen mode such as the Na–O stretching mode. The present results suggest that the interpretation of the FTIR spectrum of Na-rich beryl needs to be carefully reconsidered. | |
| Handle: | http://hdl.handle.net/11590/124125 | |
| Appare nelle tipologie: | 1.1 Articolo in rivista |
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