Balan E., Fritsch Emmanuel, Radtke G., Paulatto L., Juillot Farid, Baron F., Petit S. (2021). First-principles modeling of the infrared spectrum of Fe- and Al-bearing lizardite. European Journal of Mineralogy, 33 (5), p. 647-657. ISSN 0935-1221.
Titre du document
First-principles modeling of the infrared spectrum of Fe- and Al-bearing lizardite
Balan E., Fritsch Emmanuel, Radtke G., Paulatto L., Juillot Farid, Baron F., Petit S.
Source
European Journal of Mineralogy, 2021,
33 (5), p. 647-657 ISSN 0935-1221
The theoretical vibrational properties of a series of Fe- and Al-bearing lizardite models have been determined at the density functional theory level. Each periodic model displays a single cationic impurity substituted at an octahedral or tetrahedral site of a supercell of lizardite (Mg3Si2O5(OH)(4)) containing 162 atoms. The isovalent Fe2+ for Mg2+ substitution has been considered, as well as the heterovalent substitution of Fe3+ or Al3+ for Mg2+ or Si4+. Comparison of the theoretical absorption spectra with previously reported experimental spectra of natural and laboratory-grown lizardite samples allows us to propose an interpretation for most of the observed bands. Although the identification of specific bands related to octahedral Fe2+ in FTIR spectra is challenging, broad bands at 3584 and 3566 cm(-1) reflect the occurrence of octahedral Al3+ and Fe3+, respectively, in the natural samples. These broad bands likely overlap with potential contribution related to tetrahedral Al3+. It is suggested that the modification of the H-bonding pattern related to the incorporation of trivalent ions at tetrahedral sites has an overall broadening effect on the interlayer-OH stretching bands of lizardite.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Géologie et formations superficielles [064]
