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| DC Field | Value | Language |
|---|---|---|
| dc.contributor.author | Kamitsos, E. I. | en |
| dc.contributor.author | Yiannopoulos, Y. D. | en |
| dc.contributor.author | Karakassides, M. A. | en |
| dc.contributor.author | Chryssikos, G. D. | en |
| dc.contributor.author | Jain, H. | en |
| dc.date.accessioned | 2015-11-24T17:37:48Z | - |
| dc.date.available | 2015-11-24T17:37:48Z | - |
| dc.identifier.issn | 0022-3654 | - |
| dc.identifier.uri | https://olympias.lib.uoi.gr/jspui/handle/123456789/14406 | - |
| dc.rights | Default Licence | - |
| dc.subject | alkali germanate glasses | en |
| dc.subject | x-ray-diffraction | en |
| dc.subject | vibrational spectroscopy | en |
| dc.subject | reflectance spectra | en |
| dc.subject | na2o-geo2 glasses | en |
| dc.subject | silicate-glasses | en |
| dc.subject | borate glasses | en |
| dc.subject | vitreous geo2 | en |
| dc.subject | coordination | en |
| dc.subject | absorption | en |
| dc.title | Raman and infrared structural investigation of xRb(2)O center dot(1-x)GeO2 glasses | en |
| heal.type | journalArticle | - |
| heal.type.en | Journal article | en |
| heal.type.el | Άρθρο Περιοδικού | el |
| heal.identifier.primary | 10.1021/jp960434+ | - |
| heal.identifier.secondary | <Go to ISI>://A1996UW68500036 | - |
| heal.language | en | - |
| heal.access | campus | - |
| heal.recordProvider | Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Μηχανικών Επιστήμης Υλικών | el |
| heal.publicationDate | 1996 | - |
| heal.abstract | Infrared reflectance and Raman spectra of rubidium germanate glasses, xRb(2)O .(1 - x)GeO2, have been measured and studied as a function of Rb2O mole fraction in the range 0 less than or equal to x less than or equal to 0.60. The spectra of corresponding crystalline germanate phases, GeO2-quartz, GeO2-rutile, Rb2Ge4O9, K4Ge9O20, K2Ge2O5, and K2GeO3, have been also measured for a better understanding of the glass spectra. At very low content (x less than or equal to 0.01) Rb2O was found to induce a redistribution of GeO4 tetrahedra in rings smaller than those encountered in quartz- and glassy GeO2. The spectral manifestations of this trend are the frequency increase of the Raman active symmetric stretching vibration of Ge-O-Ge bridges and the parallel decrease of the infrared frequency of the asymmetric stretching of Ge-O-Ge bridges, Beyond the composition x = 0.01 and up to x approximate to 0.15-0.20, the predominant modification mechanism involves the transformation of GeO4 tetrahedra into GeO6 octahedra, with characteristic Raman scattering at 315, 590, and 630 cm(-1). At higher alkali content and up to the limits of glass formation, tetrahedral Q(n) species with nonbridging oxygens are formed ((4 - n) is the number of nonbridging oxygens per tetrahedron). Thus, Q(3) appears beyond x = 0.10, giving place to Q(2) (x > 0.30), Q(1) (x > 0.50), and Q(0) (x = 0.60). The characteristic Raman bands of these germanate tetrahedra were measured at 865, 765, 740, and 720 cm(-1), respectively, Based on semiempirical models, the spectroscopic results were quantified to yield the average coordination number of Ge atoms, as well as the fraction of Ge atoms in 6-fold coordination. Both were found to exhibit a maximum value at approximately 15 mol % Rb2O. | en |
| heal.publisher | American Chemical Society | en |
| heal.journalName | Journal of Physical Chemistry | en |
| heal.journalType | peer reviewed | - |
| heal.fullTextAvailability | TRUE | - |
| Appears in Collections: | Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά) | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| Karakassides-1996-Raman and infrared structural.pdf | 290.78 kB | Adobe PDF | View/Open Request a copy |
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