Application of the geometry (HOMA, EN, GEO) and magnetism based (NICS, NICS(1)) indices of aromaticity to optimised geometry of the ring in 12 meta – and 12 para – substituted benzoic acids and their anions by use of DFT computations at B3LYP/6-311+G(d,p) level has shown a very low substituent effect on the π-electron delocalisation. This resembles (qualitatively) the resistance of benzene (and...

We make use of the classical correspondence between Kekulé structures and lattice paths to obtain explicit formulas for the Pauling bond order of edges in benzenoid parallelograms. These formulas are further used to establish the average π-electron content of hexagonal rings in such benzenoids. We then compare this quantity with the atom-based π-electron content of rings, and study the local an...

¯ d − ¯ u asymmetry and semi-inclusive production of pions in DIS Abstract We investigate unambiguities in the extraction of the ¯ d − ¯ u asymmetry from semi-inclusive production of pions in DIS. The role of several effects beyond the quark-parton model (QPM) which lead to N π + p = N π + n and N π − p = N π − n and may therefore cloud such an extraction is studied. The results are discussed i...

Paramagnetic suppression in TTTA at pressure is caused by a steady decrease the separation between moieties containing radical electron along π-stacking chains with no phase transition.

Charge-transfer (CT) π-complexes are formed between planar porphyrins and 1,4,5,8,9,12-hexaazatriphenylene (HAT) derivatives with large formation constants (e.g., 104 M-1), exhibiting broad CT absorption bands. The unusually large formation constants result from close face-to-face contact between two planar π-planes of porphyrins and HAT derivatives. The redox potentials of porphyrins and HAT d...

topological analysis has been performed on the total electron density of the two forms of ozonemolecule,c2v and d3h ,to investigate the nature of chemical bonds ,molecular structure , atomiccharges and electrical properties. while these concepts have been completely discussed usingclassical models the emphasize in this work is based on quantum theory of atoms in molecules(qtaim). because the d3...

Under single scattering conditions, water droplets clouds do not depolarize the backscattered light. However, backscattered light from multiple scattering will be depolarized. The level of depolarization is a function of the droplets size, the cloud extinction coefficient value and profile; it has also an important dependency on the lidar field-of-view (FOV). The use of depolarization informati...

Casiopeínas® are copper complexes with the general formula [Cu(N-N)(N-O)]NO(3) and [Cu(N-N)(O-O)]NO(3) where N-N denotes a substituted bipyridine or phenanthroline, N-O indicates α-aminoacidate or peptide and O-O represents acetylacetonate or salicylaldehyde. This family of compounds has been evaluated in vitro and in vivo showing cytotoxic, genotoxic, and antineoplastic activity. The action me...

The LHC is the first proton accelerator for which synchrotron radiation becomes noticeable. At a beam energy of 7 TeV, the relativistic γ factor is comparable to that of electron or positron beams in the B factories or at many light sources. This means that the same number of synchrotron-radiation photons are emitted per proton and turn. The critical photon energy of about 44 eV in the LHC is n...