First-principles modeling of the infrared spectrum of Fe- and Al-bearing lizardite

Abstract. The theoretical vibrational properties of a series Fe- and Al-bearing lizardite models have been determined at the density functional theory level. Each periodic model displays single cationic impurity substituted an octahedral or tetrahedral site supercell (Mg3Si2O5(OH)4) containing 162 atoms. isovalent Fe2+ for Mg2+ substitution has considered, as well heterovalent Fe3+ Al3+ Si4+. Comparison absorption spectra with previously reported experimental natural laboratory-grown samples allows us to propose interpretation most observed bands. Although identification specific bands related in FTIR is challenging, broad 3584 3566 cm−1 reflect occurrence Fe3+, respectively, samples. These likely overlap potential contribution Al3+. It suggested that modification H-bonding pattern incorporation trivalent ions sites overall broadening effect on interlayer-OH stretching lizardite.