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International Journal of Spectroscopy
Volume 2013 (2013), Article ID 923739, 6 pages
http://dx.doi.org/10.1155/2013/923739
Research Article

Orientation and Optical Polarized Spectra (380–900 nm) of Methylene Blue Crystals on a Glass Surface

Department of Mineralogy, Crystallography, Petrology and Geochemistry, Faculty of Mining and Geology, University of Belgrade, Djušina 7, 11000 Belgrade, Serbia

Received 12 March 2013; Accepted 26 June 2013

Academic Editor: Jaan Laane

Copyright © 2013 Maja D. Milošević et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The crystallographic directions of the crystal toward the vector of polarized light can accurately be positioned, so the information that we gain from polarized spectra can be consistently interpreted according to known crystal structure. The orientation and optical properties of the methylene blue (MB) crystals were analyzed by XRD, XRPD, and polarized VIS-NIR spectroscopy. Cationic dye, MB, was polymerized into crystals on a glass slate. The blue color crystals showed pronounced dichroism, twin lamellar structure and bladed to fibrous habit. According to XRD data, [010] direction lies perpendicular to the crystal surface, so we recognized it as (0k0) face, while [100] and [001] directions coincide with crystal elongation and crystal thickness respectively. In this paper, the polarized spectra of MB crystal are presented, measured with the aim of acquisition of referent values, which could be helpful for the identification of MB molecular aggregation.