Experimental determinations and quantum-chemical calculations of the vibrational spectra of β-ZnB4O7 and β-CaB4O7
| Autor: | Gerhard Sohr, Hubert Huppertz, Reinhard Kaindl |
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| Rok vydání: | 2013 |
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Molecular Absorption spectroscopy Chemistry Analytical chemistry Ab initio Spectrum Analysis Raman Atomic and Molecular Physics and Optics Hot band Spectral line Analytical Chemistry symbols.namesake Molecular vibration Borates Spectroscopy Fourier Transform Infrared symbols Quantum Theory Wavenumber Fourier transform infrared spectroscopy Oxygen Compounds Raman spectroscopy Instrumentation Spectroscopy |
| Zdroj: | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 116:408-417 |
| ISSN: | 1386-1425 |
| DOI: | 10.1016/j.saa.2013.07.072 |
| Popis: | The two oxoborates β-ZnB4O7 and β-CaB4O7 were synthesized and investigated by FTIR- and Raman spectroscopy and ab initio quantum chemical calculations. Maximum and mean deviations between experimentally determined bands and calculated modes ranged between 15–36 cm−1 and 5–7 cm−1, respectively, allowing band assignments to vibrational modes in most cases. The complex network structures with tetrahedral BO4 and planar OB3 groups are mirrored by the spectra and numerous vibrational modes, not assignable by standard borates classification schemes. It was confirmed that OB3 units, despite similar force constants and geometry, do not absorb in the same range as BO3 units. Bands in the high wavenumber range are rather caused by B–O–(Zn/Ca), O–B–O, B–O–B, and B–O stretching and bending vibrations. The experimental observation of inactive or Raman-active modes in the absorption spectra indicates defects or structural distortions in both compounds. |
| Databáze: | OpenAIRE |
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