https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:32917 x WO₃) are vividly coloured metallic materials where the optical behaviour can be attributed to the bulk plasma frequency occurring in the visible part of the spectrum. A combination of density functional theory (DFT) calculations and experimental electron energy-loss spectroscopy (EELS) was used to assess their bulk and surface plasmon responses. It was observed that Na_x WO₃ can sustain strong localised surface plasmon resonances (LSPR) with an energy that can be tuned by changing the Na content. They have a stronger plasmonic response when compared to Au and do not suffer from the atmospheric corrosion of Ag, giving them good potential for plasmonic applications]]> Wed 02 Jun 2021 20:44:08 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:54416 Tue 27 Feb 2024 13:57:07 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:996 Sat 24 Mar 2018 08:29:49 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20347 6h-symmetry is determined by two factors - viz. the disruption of the p-conjugation of the HGF and the geometrical deformation of the HGF structure. The thermodynamically most stable structure is achieved when the former factor is minimized, and the latter factor is simultaneously maximized. Infrared (IR) spectra computed using DFT and DFTB reveal a close correlation between the relative thermodynamic stabilities of the oxidized HGF structures and their IR spectral activities. The most stable oxidized structures exhibit significant IR activity between 600 and 1800 cm⁻¹, whereas less stable oxidized structures exhibit little to no activity in this region. In contrast, Raman spectra are found to be less informative in this respect.]]> Sat 24 Mar 2018 08:02:57 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21152 Sat 24 Mar 2018 08:00:17 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:3410 Sat 24 Mar 2018 07:21:36 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:3500 Sat 24 Mar 2018 07:20:36 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25150 Sat 24 Mar 2018 07:17:09 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:35470 3−δ perovskites are attractive candidates for high-temperature mixed ionic electronic conduction processes, due to their ability to produce mixed oxidation states and accommodate oxygen vacancies. Here, we examine the electronic structure and high-temperature thermochemistry of stoichiometric and non-stoichiometric cubic BaZrO_3−δ perovskites for high defect concentration (δ = 0-0.5) using first-principles density functional theory (DFT) and density functional perturbation theory (DFPT) calculations. Our results show that the electronic structures of these perovskites under increasing oxygen deficiency are characterized by highly localized reduction of Zr⁴⁺ t_2g orbitals in the vicinity of the oxygen defects, irrespective of the value of δ. Temperature dependent thermodynamic properties of pristine- and defective-BaZrO_3−δ show consistency with oxygen vacancy concentration. A comparison of predicted thermochemical properties with and without explicit vibrational corrections demonstrates their relative stability and implications at high-temperatures, as reduction Gibbs free energies in BaZrO_3−δ exhibit large deviations above 1000 K. We elucidate the physical origins of these deviations via a phonon mode analysis.]]> Mon 22 Jun 2020 13:28:55 AEST ]]>