The electroluminescence from PPV and the blue light emission from PPP constitute exciting subjects of study. The band gap of these semiconducting polymers can be engineered in a wide range from red to ultraviolet by structural changes made on them. In the present work, we present a theoretical approach based on semiempirical and ab initio total energy and force calculations of PPV and PPP. We p...

X-ray absorption and its dependence on the polarization of light is a powerful tool to investigate the orbital and spin moments of magnetic materials and their orientation relative to crystalline axes. Here, we present a program for the calculation of dichroic spectra from first principles. We have implemented the calculation of x-ray absorption spectra for left and right circularly polarized l...

Isocyanic acid, HNCO, the imide of carbon dioxide, was prepared by reaction of stearic acid and potassium cyanate (KOCN) at 60 °C in a sealed, thoroughly dried reactor. Interestingly, its crystal structure, solved by X-ray single crystal diffraction at 123(2) K, shows a group-subgroup relation for the NCO- anion to carbon dioxide: (for CO2, cP12, Pa3̅, a = 5.624(2) Å, 150 K, C-O 1.151(2) Å; for ...

We investigate the effect of hydrogen coverage on the optical conductivity of single-side hydrogenated graphene from first-principles calculations. To account for different degrees of uniform hydrogen coverage we calculate the complex optical conductivity for graphene supercells of various sizes, each containing a single additional hydrogen atom. We use the linearized augmented plane wave metho...

γ-Al2O3 is a porous metal oxide and described as a defective spinel with some cationic vacancies. In this work, we calculate the electronic density of states and band structure for the bulk of this material. The calculations are performed within the density functional theory using the full potential augmented plan waves plus local orbital method, as embodied in the WIEN2k code. We show that the...