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Based on density functional theory (DFT), the geometric structures, stability as well as electronic and spectral properties of P2On (1 ≤ n ≤ 10) clusters are studied by using the Gaussian 09 software. The energy gap of the clusters first increases and then decreases with the increasing number n of O atoms, and P2O6 exhibits the largest energy gap and hence the highest chemical stability among the clusters. On account of the largest distance between the two peaks on both side of the Fermi energy level in density of state (DOS) for P2O6 in the clusters, which may support the highest stability of this system. The ultraviolet–visible (UV–Vis) spectra are also calculated. P2O2 is likely to be applied as potential UV-absorbing materials in view of the relatively strong absorption in UV region. Meanwhile, P2O7 has the most extensive and strongest absorption in visible region and may exhibit the best visible light activity and potential visible light catalytic performance. [ABSTRACT FROM AUTHOR]

For 3d1 (V4+) impurity in 30PbO‐5Bi2O3‐(65‐x)SiO2 glass systems with different concentrations x of V2O5, the defect structures and gyromagnetic factors are theoretically investigated by using the perturbation formulas of g factors for a tetragonally compressed octahedral 3d1 group. The concentration dependences of d‐d transition band and g factors are suitably explained from the Fourier type concentration functions of the cubic crystal field parameter Dq, covalency factor N and relative tetragonal compression ratio ρ. The above concentration dependences of these quantities are suitably illustrated by the modifications of the local crystal field strength and electron cloud distribution with increasing x. The concentration variations of the electrical conductivity and dielectric relaxation are further analyzed from the stability of the systems in view of two competitive factors (increasing network polymerization and bulk stability at low concentrations and decreasing former SiO2 and stability at high concentrations). [ABSTRACT FROM AUTHOR]

The local structural, electronic, optical, and electron paramagnetic resonance (EPR) properties are uniformly studied for Cu2+‐doped rutile (TiO2) crystals by using the density functional theory (DFT) calculations. The local cation–oxygen bond lengths and planar bond angle, band gap, Mulliken charge and overlapping population, density of state (DOS), and UV–Vis absorption spectra are calculated for pure and copper‐doped rutile. The smaller overlapping population of Cu–O bonds in the doped system than Ti–O bonds in pure rutile reflects weaker orbital admixtures or covalency of the former. Compared with pure rutile, Cu2+ doping leads to significant redshift of the UV–Vis absorption band and the narrow impurity band in visible and near‐infrared regions arising from the Cu2+ d–d transitions and narrowing of the band gap by about 0.636 eV, possibly suggesting enhancement of visible light activity. The Cu dopant induces a spin magnetic moment of 0.74 μB for the doped rutile. The calculated UV–Vis absorption spectra and spin Hamiltonian parameters for copper‐doped rutile show reasonable agreement with the experimental data and some improvement related to the previous perturbation formula calculations. Present systematic studies would be helpful to understand the mechanisms of the enhancement in the optical and magnetic properties of this material with transition‐metal (especially Cu2+) dopants. [ABSTRACT FROM AUTHOR]