Publications des scientifiques de l'IRD

Crepisson C., Bureau H., Blanchard M., Ingrin J., Balan Etienne. (2014). Theoretical infrared spectrum of partially protonated cationic vacancies in forsterite. European Journal of Mineralogy, 26 (2), p. 203-210. ISSN 0935-1221.

Titre du document
Theoretical infrared spectrum of partially protonated cationic vacancies in forsterite
Année de publication
2014
Type de document
Article référencé dans le Web of Science WOS:000334918100001
Auteurs
Crepisson C., Bureau H., Blanchard M., Ingrin J., Balan Etienne
Source
European Journal of Mineralogy, 2014, 26 (2), p. 203-210 ISSN 0935-1221
Hydroxyl defects in pure forsterite are usually ascribed to incorporation of protons fully compensating the electrostatic charge of cationic vacancies. However, partially compensated vacancies have been predicted from theoretical considerations. Here, we theoretically determine the structural, vibrational and infrared spectroscopic properties of partially protonated cationic vacancies in forsterite using a first-principles theoretical modeling approach. The results show that the partial protonation of Si vacancies strongly modifies their spectroscopic properties with respect to those of the fully protonated (4H)(Si)(x) defect, leading to a significant downshift of at least one of the OH-stretching absorption bands. Comparison with experimental observations shows that such defects are unlikely to significantly contribute to the speciation of OH groups in pure synthetic forsterite samples. A partial protonation of Mg vacancies has a weak effect on the spectroscopic properties of OH groups, compared with those of the fully protonated defect, making it difficult to assess their occurrence from spectroscopic observations only.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Géologie et formations superficielles [064]
Localisation
Fonds IRD [F B010062037]
Identifiant IRD
fdi:010062037
Contact