OH defects in forsterite |
| |
| Authors: | Eugen Libowitzky Anton Beran |
| |
| Institution: | 1. Institut für Mineralogie und Kristallographie, Universit?t Wien — Geozentrum, Althanstra?e 14, A-1090, Wien, Austria
|
| |
| Abstract: | Polarized FTIR spectra of near endmember forsterite single crystals from Pamir, Tadzikistan show the existence of sharp strongly pleochroic absorption bands in the region of the OH stretching fundamental. Bands centered at 3674/3624, 3647/3598 and 3640/ 3592 cm-1 are attributed to OH dipoles oriented parallel to 100]. An OH band doublet at 3570/3535 cm-1 shows both, a strong absorption parallel to 100] and a strong component parallel to 001]. On the basis of the pleochroic scheme and under the assumption of vacancies on Si- and M-sites it is proposed that O1 is partially replaced by OH defects pointing to the vacant Si-site. O3 is donator oxygen of OH dipoles lying near the O3-O1 tetrahedral edge or roughly pointing to a vacant M2-site. Also O2 can act as donator oxygen of an OH group oriented along the O2-O3 edge of a vacant M1 octahedron. The splitting of the bands is explained by the presence of Fe2+ in cation sites surrounding the OH defects. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
