Raman spectroscopy under high pressures and DFT calculations of the amino acid l-glutamine
l-glutamine crystal was obtained by the slow evaporation method and its crystallographic structure was verified by X-ray diffraction experiments and the Rietveld method. The vibrational modes of l-glutamine were investigated through Raman spectroscopy and the normal modes were obtained using the Den...
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Published in | Vibrational spectroscopy Vol. 98; pp. 69 - 76 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Amsterdam
Elsevier B.V
01.09.2018
Elsevier BV |
Subjects | |
Online Access | Get full text |
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Summary: | l-glutamine crystal was obtained by the slow evaporation method and its crystallographic structure was verified by X-ray diffraction experiments and the Rietveld method. The vibrational modes of l-glutamine were investigated through Raman spectroscopy and the normal modes were obtained using the Density Functional Theory with the B3LYP functional and set of bases 6-31G++(d, p). With such approach, it was possible to make a theoretical-experimental comparison of the results obtained and to furnish a more precise assignment of the normal modes. The crystal was submitted to high pressure conditions and the Raman spectra between 3055 and 40 cm−1 were recorded for pressures up to 6.1 GPa in a diamond anvil cell. This study allowed us to understand that the crystal undergoes a reversible structural phase transition around 4.0 GPa, characterized mainly by spectral changes in the region of the external modes. |
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ISSN: | 0924-2031 1873-3697 |
DOI: | 10.1016/j.vibspec.2018.07.004 |