Academic Journal
Vibrational States in Opals Revisited
| العنوان: | Vibrational States in Opals Revisited |
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| المؤلفون: | G. Ivanov, V., Aguilar Reyes, B., Fritsch, E., Faulques, Eric |
| المساهمون: | Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS) |
| المصدر: | ISSN: 1932-7447. |
| بيانات النشر: | HAL CCSD American Chemical Society |
| سنة النشر: | 2011 |
| المجموعة: | Université de Nantes: HAL-UNIV-NANTES |
| مصطلحات موضوعية: | [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] |
| الوصف: | International audience ; Quantitative assessment of the vibrational features of nanocrystalline hydrated silicas is still not yet ascertained, although this is a relevant issue in silica physics. In this work, we examine the vibrational states in two generic opaline silicas. PM3 semiempirical calculations on finite SiO2hydrated clusters prove that the low-frequency Raman lines experimentally observed at 307, 340, and 370 cm-1 and the high-frequency ones at 790 cm-1 and 1080 cm-1 stem from O-Si-O bending vibrations in six-membered rings of corner-shared SiO4 tetrahedra and O-Si-O symmetric/asymmetric stretch vibrations, respectively. Lattice dynamical calculations on crystalline silica polymorphs show that the predominance of tridymite over cristobalite in opaline silicas cannot be established due to the intrinsic nanoscale crystalline order of the materials. We conclude that the vibrational variations observed between opaline silicas are due to gradual formations of six-membered rings in a disordered SiO2 matrix. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| Relation: | hal-00849732; https://hal.science/hal-00849732 |
| DOI: | 10.1021/jp2027115 |
| الاتاحة: | https://hal.science/hal-00849732 https://doi.org/10.1021/jp2027115 |
| رقم الانضمام: | edsbas.D2042B51 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1021/jp2027115 |
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