Theoretical study of OH-defects in pure enstatite - Université Paris Cité Accéder directement au contenu
Article Dans Une Revue Phys Chem Minerals Année : 2013

Theoretical study of OH-defects in pure enstatite

Résumé

The infrared spectroscopic properties of selected defects in orthoenstatite are investigated by first-principles calculations. The considered defects include doubly protonated Mg vacancies at M1 and M2 sites, fully protonated SiA and SiB vacancies (hydrogarnet defects), and doubly protonated SiA and SiB vacancies associated with interstitial Mg2? cations. The bands observed at 3,070 and 3,360 cm-1 in the spectrum of synthetic enstatite samples are ascribed to O2A-H and O2B-H groups, respectively, associated with M2 vacancies. The theoretical models suggest that bands observed at 3,590 and 3,690 cm-1 in the spectrum of enstatite samples synthesized under low silicaactivity conditions correspond to O2H and O1H groups associated with SiB vacancies partially compensated by interstitial Mg2? cations in fivefold coordination. The theoretical relation between the integrated absorption coefficient of OH-defects and vibrational frequencies is consistent with previous observations indicating that the absorption coefficients of OH-defects are comparatively stronger in enstatite than in the olivine polymorphs

Domaines

Minéralogie

Dates et versions

hal-01010563 , version 1 (20-06-2014)

Identifiants

Citer

Etienne Balan, Marc Blanchard, Haohao Yi, Jannick Ingrin. Theoretical study of OH-defects in pure enstatite. Phys Chem Minerals, 2013, 40, pp.41-50. ⟨10.1007/s00269-012-0544-6⟩. ⟨hal-01010563⟩
145 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More