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Isosbestic-like point in the polarized reflectance spectra of monoclinic crystals—A quantitative approach
- Source :
-
Spectrochimica Acta Part A: Molecular & Biomolecular Spectroscopy . Nov2007, Vol. 68 Issue 3, p632-638. 7p. - Publication Year :
- 2007
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Abstract
- Abstract: If two overlapping bands originate from transition moments that are perpendicular and lie along the principal axes of the infinity frequency dielectric tensor, an isosbestic-like point (ILP) appears in the overlaid polarized IR reflectance spectra of single crystals. These conditions can also be met in principle in case of the reflectance from the ac-plane of a monoclinic crystal despite of the crystal''s low symmetry. In order to determine the transition moment directions, diagonalization of the infinity frequency dielectric tensor should be performed. It is shown that a critical magnitude for the appearance of ILP is the angle of incidence. An increase of this angle leads to a transformation of the ILP to an isosbestic-like region, which eventually vanishes at higher incidence angles. Polarized reflectance spectra of gypsum (CaSO4·2H2O), recorded from the ac crystal face, were used to verify the theoretical results. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 13861425
- Volume :
- 68
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Spectrochimica Acta Part A: Molecular & Biomolecular Spectroscopy
- Publication Type :
- Academic Journal
- Accession number :
- 27002015
- Full Text :
- https://doi.org/10.1016/j.saa.2006.12.039