Molecular γ-amino butyric acid and its crystals: Structural, electronic and optical properties
This work presents the formation of monoclinic γ-aminobutyric acid (GABA) crystals grown from an aqueous ethanol solution with the dimensions 4 × 1 × 0.6 mm3. The structural properties of the grown crystal were evaluated via X-ray diffraction analysis of the powder and single crystal, which con...
- Autores:
-
Silva, José Barbosa
Echeverry, Juan Pablo
dos Santos, Regina Claudia Rodrigues
de Paula, Valdir Ferreira
Guedes, Maria Izabel Florindo
e Silva, Bruno Poti
Valentini, Antoninho
Caetano, Ewerton Wagner Santos
Freire, Valder Nogueira
- Tipo de recurso:
- Article of journal
- Fecha de publicación:
- 2023
- Institución:
- Universidad de Ibagué
- Repositorio:
- Repositorio Universidad de Ibagué
- Idioma:
- eng
- OAI Identifier:
- oai:repositorio.unibague.edu.co:20.500.12313/3841
- Acceso en línea:
- https://hdl.handle.net/20.500.12313/3841
- Palabra clave:
- DFT calculations
GABA polymorphs Crystals
Optical properties
Structural properties
γ-amino butyric acid (GABA) crystal
- Rights
- openAccess
- License
- http://purl.org/coar/access_right/c_abf2
| Summary: | This work presents the formation of monoclinic γ-aminobutyric acid (GABA) crystals grown from an aqueous ethanol solution with the dimensions 4 × 1 × 0.6 mm3. The structural properties of the grown crystal were evaluated via X-ray diffraction analysis of the powder and single crystal, which confirmed a monoclinic crystal system with space group P21/c. Thermal stability and the melting point of the synthesized GABA crystal were investigated using TG-DSC measurements. We also characterized experimentally monoclinic and molecular GABA solvated in water, obtaining its optical absorption spectrum in the UV-VIS region. Time-dependent DFT calculations were performed for the GABA molecule in the neutral and zwitterion forms to understand their optical absorption features. Structural, electronic, and optical properties of four γ-aminobutyric acid (GABA) crystal polymorphs (monoclinic, tetragonal, hexagonal, and monohydrate) were achieved through DFT calculations employing a dispersion corrected exchange-correlation functional. Differences in the electronic and optical properties between polymorphs are discussed. We predict the GABA monoclinic crystal to be an indirect gap semiconductor with a gap value of 5.02 eV, in good agreement with our experimental measurements. Considering the other three polymorphs, their fundamental gap values range from 4.6 eV to 5.16 eV (being direct for all of them, except the monohydrate). The absorption spectra calculations reveal a significant optical anisotropy for all GABA crystals, with the highest optical absorption for the monoclinic structure in the 5–6 eV energy range |
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