Growth, EPR and optical absorption spectra of l-threonine single crystals doped with Cu2+ ions

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dc.creatorSantana, Ricardo Costa de
dc.creatorSantos, Marcilene Gomes dos
dc.creatorCunha, R. O.
dc.creatorFerreira, Katiúscia Daiane
dc.creatorCarvalho, Jesiel Freitas
dc.creatorCalvo, Rafael
dc.date.accessioned2024-07-11T14:46:47Z
dc.date.available2024-07-11T14:46:47Z
dc.date.issued2007
dc.description.abstractWe investigated the crystal growth, electron paramagnetic resonance (EPR) and optical absorption spectra of l-threonine doped with Cu2+. The quality, size and habit of the single crystals grown from aqueous solution by the slow solvent evaporation and by the cooling methods vary when the impurities are introduced during the growth process. The variations with the magnetic field orientation of the EPR spectra of single-crystal samples at room temperature and 9.77 GHz in three crystal planes (ab, bc and ac) show the presence of copper impurities in four symmetry-related sites of the unit cell. These spectra display well resolved hyperfine couplings of the of Cu2+ with the ICu= of the copper nuclei. Additional hyperfine splittings, well-resolved only for specific orientations of the magnetic field, indicate that the copper impurity ions in the interstitial sites have two N ligands with similar hyperfine couplings. The principal values of the g and ACu tensors calculated from the EPR data are g1=2.051(1), g2=2.062(2), g3=2.260(2), ACu,1=16.9(5)×10−4 cm−1, ACu,2=21.8(6)×10−4 cm−1, ACu,3=180.0(5)×10−4 cm−1. The principal directions corresponding to g3 and to ACu,3 are coincident within the experimental errors, reflecting the orientation of the bonding planes of the copper ions in the crystal. The values of the crystal field energies are evaluated from the optical absorption spectrum, and the crystal field and bonding parameters of the Cu impurities in the crystal are calculated and analyzed. The EPR and optical absorption results are discussed in terms of the crystal structure of l-threonine and the electronic structure of the Cu2+ ions, and compared with data reported for other systems. The effects of the impurities in the growth and habit of the crystals are also discussed.
dc.identifier.citationSANTANA, R. C.; CUNHA, R. O.; SANTOS, M. G.; FERREIRA, K. D.; CARVALHO, J. F.; CALVO, R. Growth, EPR and optical absorption spectra of L-threonine single crystals doped with Cu2+ ions. Journal of Physics and Chemistry of Solids, Amsterdam, v. 68, n. 4, p. 586-593, 2007. DOI: 10.1016/j.jpcs.2007.01.043. Disponível em: https://www.sciencedirect.com/science/article/pii/S0022369707000480. Acesso em: 26 maio 2023.
dc.identifier.doi10.1016/j.jpcs.2007.01.043
dc.identifier.issn0022-3697
dc.identifier.issne- 1879-2553
dc.identifier.urihttps://www.sciencedirect.com/science/article/pii/S0022369707000480
dc.language.isoeng
dc.publisher.countryHolanda
dc.publisher.departmentInstituto de Física - IF (RMG)
dc.rightsAcesso Restrito
dc.subjectA. Organic compound
dc.subjectB. Crystal growth
dc.subjectD. Electron paramagnetic resonance (EPR)
dc.subjectD. Crystal fields
dc.titleGrowth, EPR and optical absorption spectra of l-threonine single crystals doped with Cu2+ ions
dc.typeArtigo

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