Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7690531 | Vibrational Spectroscopy | 2018 | 24 Pages |
Abstract
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 40âcmâ1 were recorded for pressures up to 6.1âGPa in a diamond anvil cell. This study allowed us to understand that the crystal undergoes a reversible structural phase transition around 4.0âGPa, characterized mainly by spectral changes in the region of the external modes.
Keywords
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Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
R.O. Holanda, C.B. Silva, J.G. Silva Filho, C.L. Lima, J.A. Lima, P.T.C. Freire,