Two types of annulene which may show significant Möbius aromatic character and bond and twist delocalisation are proposed; triplet states with 4n + 2 occupancy of the p pi array of atomic orbitals and a novel 8-pi carbeno[8]heteroannulene ring system 1 where the Hückel highly antiaromatic nature as a planar system can be attenuated or even reversed by the C2 symmetric Möbius distortion.

Singly N-confused [26] and [28]hexaphyrins (4, 5) with planar and twisted structures, respectively, were prepared via the acid catalyzed [3 + 3] condensation of N-confused and regular tripyrrane precursors. Hückel aromaticity is observed for [26]hexaphyrin, while the [28]hexaphyrin and its mono-Pd(II) complex exhibit "nonaromaticity" in spite of their Möbius-type structures, judging from the sp...

A system of three electrolytes separated by two parallel planes is considered. Each region is described by a dielectric constant and a Coulomb fluid in the Debye-Hückel regime. In their book Dispersion Forces, Mahanty and Ninham have given the van der Waals free energy of this system. We rederive this free energy by a different method, using linear response theory and the electrostatic Maxwell ...

In this extension of the main IET tutorial, we will deal with the mis-alignment issue that is inherent in Extended Hückel (EH) theory. In such method, the energies of states in different materials are parametrized differently. As a result, the position of the Fermi levels (EF ) of different materials are not referenced to the same vacuum energy. [1] This causes an issue in that a supercell cont...

This work presents a finite volume method used to solve the relevant coupled equations for general electro-osmotic flows of viscoelastic fluids, using the upper-convected Maxwell and the simplified Phan-Thien–Tanner models. Three different implementations of the electro-osmosis physical models were carried out, which depend on the required level of approximation. In the first implementation, th...

We present several aspects of the screening of charged macromolecules in an electrolyte. After a review of the basic mean field approach, based on the linear Debye-Hückel theory, we consider the case of highly charged macromolecules, where the linear approximation breaks down and the system is described by the full nonlinear Poisson-Boltzmann equation. Some analytical results for this nonlinear...

Coronoids with holes shaped like an odd carbon benzenoid have antiaromatic holes and antiaromatic conjugated circuits. Another class of concealed diradical coronoids has been identified. They are Hückel molecular orbital diradicals (HOMO = LUMO = 0, each with a single electron occupancy) that have VB (valence-bond) structures (K 0).This new class of concealed diradical coronoids have more enhan...

In this paper an alternative model allowing the extension of the Debye-Hückel Theory (DHT) considering time dependence explicitly is presented. From the Electro-Quasistatic approach (EQS) introduced in earlier studies time dependent potentials are suitable to describe several phenomena especially conducting media as well as the behaviour of charged particles (ions) in electrolytes. This leads t...

Using the mixed solvents, (water +ethanol + propanol), the solubility of CdF2 was determined byevaporating method at 25° C. The results showed that the sollbility, s, of CdF2 decreases bydecreasing the dielectric constant of the mixed solvent .Once the solubility of CdF2 was determined,the concentration solubility product, Ksp(c)=4s3, was calculated .Furthermore ,by estimating the meanactivity ...