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The structural property, electronic structure and optical properties of lead-based halide perovskites CsPbF3-yIy (y = 0, 1, 2) are investigated. The computed electronic structure profile of CsPbF3-yIy (y = 0, 1, 2) reveals that these materials exhibit semiconducting behavior at normal pressure. The energy gap of CsPbF3 is tuned by substituting iodine atoms for fluorine atoms. The optical parameters, such as dielectric function, electron energy loss function, refractive index and reflectivity, are computed. The optical properties of these lead-based halide perovskites against the incident photon energy radiation indicate that these materials can be effective candidates for the solar cell applications. [ABSTRACT FROM AUTHOR]

The electronic properties and structural phase transition of bulk rhodium hydride are analyzed using density functional theory calculations with the generalized gradient approximations. The sequent phase transition is observed in bulk rhodium hydride. The predicted new high pressure phase of rhodium hydride is hexagonal NiAs type. The atomic geometry, adsorption energy, and binding energy of the Rh (111) surface are computed. The calculated surface energy for Rh (111) surface is 1.06349 eV and the maximum adsorption energy is obtained in 6 x 1 phase as 2.8617 eV. The relaxed geometries show that hydrogen has a strong influence on the interlayer distance. [ABSTRACT FROM AUTHOR]

First principles calculations are performed by using Vienna ab initio simulation package within the framework of density functional theory to understand the electronic and structural properties of yttrium, zirconium and niobium hydrides. The equilibrium lattice constant, the bulk modulus, the total density of states and charge density distribution are analyzed in comparison with the available experimental and theoretical data. The X-ray diffraction pattern is also simulated to estimate the lattice constants of these hydrides. The formation energies are computed for rock-salt and fluorite structures using density functional theory. The calculated elastic constants obey the necessary stability conditions. A detailed analysis of the changes in density of states and electron density upon hydride formation has allowed us to understand the formation of these hydrides. [ABSTRACT FROM AUTHOR]