Assessment of PBE0 for evaluating the absorption spectra of carbonyl molecules

Using the parameter‐free PBE0 hybrid functional, we compute the UV/Vis spectra of a series of solvated compounds presenting a carbonyl chromophoric unit linked to a carbon–carbon double bond. It turns out that PBE0 is extremely efficient for accurately reproducing experimental values, with a mean unsigned error of 7 nm for an extended set of compounds, although no fitting or statistical treatments are performed. PBE0 has a predictive efficiency comparable to the well‐known Woodward–Fieser empirical formula, and can therefore be used to extend these rules without requiring additional experimental results. Consequently, the UV/Vis spectra of several compounds that have not yet been synthesized are predicted. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006     

The doubly periodic Costa surfaces

We derive global Weierstrass representations for complete minimal surfaces obtained by substituting the planar end of the Costa surface by symmetry curves. Received: 14 February 2001; in final form: 24 April 2001 / Published online: 29 April 2002     

The probabilities of optical transitions in an Al2O3 crystal in the 9–30 eV range

The spectra of elementary oscillators of optical transitions in corundum in the region of 8–30 eV are determined for the first time. The parameters of the oscillators are calculated using experimental reflection spectra taken from four different papers. The main features of the spectra are established.     

Bacterial Constituents CXIII Structure Revision of Several Pyoverdins Produced by Plant-Growth Promoting and Plant-Deleterious Pseudomonas Species

The structural revision on the basis of spectroscopic and degradation results of several pyoverdins from Pseudomonas spp. is reported. Siderotyping studies by the isoelectrofocusing technique and by ferri-pyoverdin uptake experiments had prompted a re-investigation of some structures proposed in the literature.     

Optical properties and electronic structure of fluorite and corundum

The complete sets of 12 fundamental optical functions for fluorite crystals in the range 5–39 eV and corundum crystals in the range 2–30 eV are determined from the experimental and theoretical spectra known for certain of these functions. The main features and generalities of these functions are revealed. A theoretical analysis of the optical spectra obtained is performed using the known theoretical band diagrams and the spectra of ?₂.     

On maps with given Jacobians involving the heat equation

In this paper we present and analyze two new algorithms to construct a smooth diffeomorphism of a domain with prescribed jacobian function. The first one is free from any restriction on the boundary, while the second one produces a diffeomorphism that coincides with the identity map on the boundary of the domain. Both are based on the solution of an initial value problem for the linear heat equation, and the second also uses solutions of the Stokes system of Fluid Mechanics.     

Synthesis and properties of magnetic superhydrophobic mesoporous Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>–SiO<Subscript>2</Subscript> composites

Ways to obtain Fe₂O₃–SiO₂ iron-containing silica composites with organized mesoporous structure (MCM-41) and large specific surface area (up to 1476 m² g^–1) were considered. The influence exerted by the method used to synthesize the materials on their structure, texture characteristics, particle size, and magnetic properties were studied. The aggregative stability of samples was examined. It was shown that treatment of the resulting composites with compounds from the chlorosilane group affects their hydrophobic properties.     

Energetic Properties of Rocket Propellants Evaluated through the Computational Determination of Heats of Formation of Nitrogen‐Rich Compounds

The use of ab initio and DFT methods to calculate the enthalpies of formation of solid ionic compounds is described. The results obtained from the calculations are then compared with those from experimental measurements on nitrogen‐rich salts of the 2,2‐dimethyltriazanium cation (DMTZ) synthesized in our laboratory and on other nitrogen‐rich ionic compounds. The importance of calculating accurate volumes and lattice enthalpies for the determination of heats of formation is also discussed. Furthermore, the crystal structure and hydrogen‐bonding networks of the nitroformate salt of the DMTZ cation is described in detail. Lastly, the theoretical heats of formation were used to calculate the specific impulses (I_sp) of the salts of the DMTZ cation in view of a prospective application in propellant formulations.     

Coexistence of the chiral superconductivity and noncollinear magnetic order in the ensemble of Hubbard fermions on a triangular lattice

For the system of strongly correlated electrons on a triangular lattice, the possibility of coexisting superconductivity with the chiral order parameter and the 120°-type noncollinear spin ordering is demonstrated. The integral self-consistency equation for the superconducting order parameter is derived using the diagram technique for Hubbard operators taking into account the spin structure, exchange interaction within two coordination spheres, and intersite Coulomb repulsion.