Navegando por Autor "Henriques, J.M."
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Artigo Structural, optoelectronic, infrared and Raman spectra from first principles calculations of γ-Cd(OH)2(Elsevier, 2015-01) Barboza, Carlos Antonio; Henriques, J.M.; Albuquerque, E.L.; Fulco, U.L.; Moreira, E.Wehaveinvestigatedthephysicalpropertiesofthecadmiumhydroxidepolymorph γ-Cd(OH)2 using density-functional theory(DFT)consideringboththelocaldensityandgeneralizedgradientapproxima- tions, LDAandGGA,respectively.Theelectronicbandstructure,theelectronicdensityofstates,the dielectric functionandtheopticalabsorptionarecalculated.Acomparisonrevealsgoodagreementof the calculatedlatticeparameterswithexperimentalresults.Adirectbandgap EðΓ-ΓÞ ¼ 1:70 eV (1.53eV)wasobtainedwithintheGGA(LDA)levelofcalculation.Thevibrationalnormalmodesaswell as the Raman and infrared spectraof γ-Cd(OH)2 were obtained and assigned.Artigo Vibrational and thermodynamic properties of orthorhombic CaSnO3 from DFT and DFPT calculations(Elsevier, 2015-02) Barboza, Carlos Antonio; Moreira, E.; Albuquerque, E.L.; Fulco, U.L.; Henriques, J.M.; Araújo, A.I.Density functional theory (DFT) and density functional perturbation theory (DFPT) calculations were used to investigate the vibrational and thermodynamic properties of orthorhombic stannate CaSnO3 compound. Our approach was based on the generalized gradient approximation with dispersion correction (GGA+D), considering the norm-conserved pseudopotentials. The phonon dispersion relation as well as theoretical peaks of the infrared (IR) and Raman spectrum in the frequency range of 100–800 cm−1 was analyzed and assigned. The thermodynamic potentials and the specific heat at constant volume of the CaSnO3 compound are also calculated, whose dependence with the temperature are discussed.