Theoretical and experimental study of the vibrational spectra of (para)symplesite and hörnesite
Petre Makreski1, Stefan Stefov1, Ljupčo Pejov1
1Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, Arhimedova 5, 1000 Skopje, Macedonia.
Abstract:
Arsenate water-bearing minerals, hörnesite (Alšar, Macedonia) and symplesite (Laubach, Germany), were studied by vibrational (IR and Raman) spectroscopy and X-ray powder diffraction. The observed vibrational spectra in both the high (1100-600 cm(-1)) and low (600-450 cm(-1)) wavenumber regions of AsO4 and H2O vibrations could be used to discriminate the two studied minerals. Spectral differences are especially pronounced in the bending and stretching regions of the H2O vibrations in the IR spectra. The observed bands in IR and Raman spectra were tentatively assigned. To support the assignment, IR spectra were theoretically simulated. These calculations were performed using the crystal structure of parasymplesite (no structural information of symplesite has been published so far) and hörnesite using a 3D periodic plane-wave pseudopotential density functional theory approach applying various combinations of exchange-correlation functionals. In this article, we report on the first experimental study of the vibrational spectra of the very rare symplesite mineral.
Related Concept Videos
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
Raman Spectroscopy: Overview
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to...
Emission Spectra
UV–Vis Spectroscopy of Conjugated Systems
One of the factors influencing λmax is...
IR Spectroscopy: Molecular Vibration Overview
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...


