Sharif Digital Repository

The molecular behavior of some aniline derivatives as corrosion inhibitors of iron and copper in acidic media (HCl and H2 S O4) were investigated quantum-electrochemically by some recently developed models based on density functional theory and cluster/polarized continuum approaches. In this regard, electrical dipole moment, charges on hetero atoms and acidic hydrogen, electronic chemical potential, and extent of charge transfer were determined for both neutral and protonated forms of molecules inside an electrical double layer and correlated to their inhibitory powers. Good correlations were observed for both acidic media. The results were discussed via ion-pair hypothesis and deprotonation... 

Controlled rotation of a suspended soap water film, simply generated by applying an electric field, has been reported recently. The film rotates when the applied electric field exceeds a certain threshold. In this study, we investigate the phenomenon in films made of a number of other liquids with various physical and chemical properties. Our measurements show that the intrinsic electrical dipole moments of the liquid molecules seems to be vital for the corresponding film rotation. All the investigated rotating liquids have a molecular electric dipole moment of above 1 Debye, while weakly polar liquids do not rotate. However, the liquids investigated here cover a wide range of physical... 

We study the competition between spin and charge fluctuations of the extended Hubbard model with on-site and dipole-dipole interactions in a one-dimensional lattice. Using the extended two-particle self consistent (ETPSC) method, we find the corresponding expressions for spin and charge response functions. In this approach, the irreducible spin and charge vertices are a function of inter-particle distance (r) and wave-number (q). This theory allows us to determine the crossover temperatures and the dominant instability as a function of U and V. The phase diagrams are obtained for several effective particle densities: n = 0.5, n = 1 and n = 4/3. Each phase diagram (U − V − T space)... 

We theoretically investigate the effect of superconductivity on the ultrafast electron dynamics in graphene interacting with an ultrashort linearly polarized optical pulse. The optical pulse, with frequency greater than 1 THz, quadratically couples to the Higgs (amplitude) mode and therefore can excite the Higgs-mode oscillations in superconductors, leading to quenching superconducting excitation energy, even in s-wave pairing symmetry. Since the duration of the used pulse is less than the electron scattering time in graphene (10-100 fs), the electron dynamics driven by the electric field of pulse remains coherent and is described within the tight-binding model of graphene. We show that the... 

Equations of state based on the statistical associating fluid theory for potentials of variable range (SAFT-VR) and the perturbed chain statistical associating fluid theory (PC-SAFT) have been used to model the PVT behavior of ionic liquids and the solubility of H2S in six imidazolium-based ionic liquids. The studied systems included [bmim][PF6], [hmim][PF6], [bmim][BF4], [hmim][BF4], [bmim][NTF2] and [hmim][NTF2] at various temperatures and pressures.For pure components, parameters of the models have been obtained by fitting the models to experimental data on liquid densities; the average relative deviation between the calculated and experimental densities for ionic liquids is less than...