Self-consistent density functional calculations have been performed on a variety of planar conjugated Ni-centered macrocycles with a basic porphyrazine (tetraazaporphyrin) core and peripheral dithiolene groups (PZ) or fusedbenzo groups (PC). Theoretical energy level diagrams, charge distributions, and densities of states have been obtained in order to understand the electronic structure modifications due to peripheral ligand substitution. The substituents role in altering electronic properties and charge distribution of the porphyrazine macrocycles has been used to interpret the observed variations in optical absorption profiles. In the Q-band (∼680 nm) region, a single peak is seen for high symmetry (D 4h ) macrocycles and a double peak for lower symmetry (D 2h and C 2V ) systems. Calculated intensities and band splittings are compared in detail with qualitative molecular orbital models and experiment in the visible and UV regions. Predictions are made for the infrared absorption and semiconducting band gap.

Self-consistent Density Functional calculations have been performed on a variety of planar conjugated Ni-centered macrocycles with a basic tetraazaporphyrinic core and dithiolene groups (PZ) or fused-benzo groups (PC). Theoretical energy diagrams, charge and spin distributions and densities of states have been obtained in order to understand the electronic structure modifications due to peripheral ligand substitution. The substituents role in altering electronic properties and charge distribution of the porphyrazine macrocycles has been used to interpret the observed variations in optical absorption profiles. In the Q-band (∼ 680 nm) region, a single peak is seen for high symmetry (D4h) macrocycles and a double peak for lower symmetry (D2h and C2v) systems. Calculated intensities and band splittings are compared in detail with qualitative molecular orbital models and experiment in the visible and UV regions. Predictions are made for the infrared absorption and semiconducting band gap.

No abstract

Electronic structures and hypenine interactions associated with the Cu-O environment of T. Y, and T' phases of &a-,Gd,)2CuOn were d i e d . using the density functional theory in an embedded cluster approach. MGssbauer isomer shins. electric field gradients and contact h y m n e fields for Fe-substirut& species were determined for compadson with experiments performed on Fe:-Gd)L.85Sro.ISCuOd. 'Thest data are us& to describe the response of charge and spin densities around Cu sites to sixfold (T). fivefold (T), and fourfold (T') oxygen coordination.