JOURNAL OF PHYSICAL AND THEORETICAL CHEMISTRY
Year:2013 | Volume:9 | Issue:4|Papers Count:9

In this research, the effect of catalyst type on the CNTs synthesis was investigated. The carbon nanotubes (CNTs) were produced on stainless steel substrates and two of catalyst with different characteristics by using Thermal chemical vapor deposition (TCVD) method. The catalysts have the important role for the growth carbon nanotubes (CNTs). Acetylene gas (C2H2) diluted by NH3 was used as the reaction gas as a source of carbon. The formation of carbon nanotube structures were confirmed by Raman spectroscopy and scanning electron microscopy (SEM) methods. It was found that the type of catalyst play has an important role on the quality of the nanotubes.

In this research DFT/B3LYP method has been employed to investigate the geometrical structures, relative stabilities, and electronic properties of Cun (n=3–10) clusters for clarifying the effect of size on the properties. Through a careful analysis of the successive binding energies, second-order difference of energy and the highest occupied-lowest unoccupied molecular orbital energy gaps as a function of cluster size, an odd-even alternative phenomenon has been observed. The results show that the clusters with even number of copper atoms present relatively higher stabilities.

In this paper, the numerical solution methods of one- particale, one – dimensional  time- independent Schrodinger equation are presented that allows one to obtain accurate bound state eigen values and eigen functions for an arbitrary potential energy function V(x). These methods included the FEM (Finite Element Method), Cooly, Numerov and others. Here we considered the Numerov method in more details. For this purpose, we first reformulated the Shrodinger equation using dimensionless variables, the estimating the initial and final values of the reduced variable xr and the value of intervals sr, and finally making use of Q-Basic or Spread Sheet computer programs to numerically solved the equation. For each case, we drew the eigen functions versus the related reduced variable for the corresponding energies. The harmonic oscillator, the Morse potential, and the H-atom radial Schrodinger equation, … were the examples considered for the method. The paper ended with a comparison of the result obtained by the numerical solutions with those obtained via the analytical solutions. The agreement between the results obtained by analytical solution method and numerical solution for some Potential functions harmonic oscillator̕ Morse was represents the top Numerov method for numerical solution Schrodinger equation with different potentials energy.

The Density of State and the Natural Bond Orbital calculations were carried out to study the oxidation of CO on Au14 nano cluster through two different mechanisms and determining the best mechanism for the reaction. Chemisorption of O2 and CO on the nano cluster led to change in energy, density of state and its thermodynamic properties. We calculated the energy band gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital and its role in the adsorption phenomenon.

Using the mixed solvents, (water+ethanol+propanol), the solubility of CdF2 was determined by evaporating method at 25oC. The results showed that the sollbility, s, of CdF2 decreases by decreasing 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 mean activity coefficient, ¦±, of CdF2 in the solution upon the extended Debye-Huckel theory, the model solubility Product constant of the salt, Ksp(m)=4s3 ¦±3 was calculated .On the other hand we concluded the equilibrium constant of ion pair formation, KIP, on the basis of Fuoss contact ion pair model and we obtained the value of ion pair concentration in the mixed solvents, (water 85%+ethanol l5%+propanol 10%). The value of thermodynamic solubility product constant, Ksp(th), of CdF2 in the mixed solvent was evaluated at zero ionic strength upon the extrapolation method and the value of ion pair concentration was calculated in the considered solution and  compared by fuoss model.

Using the Density Functional Theory (DFT) level by means of 3-21G, 6-31G and 6-31+G (d) basis sets, the structural optimization of isolated Pyrazole and Pyrazoline was done in the gas phase. Then, the calculation about the solvent effect on the stability energies of Pyrazole and Pyrazoline was performed for the ten solvents using PCM model method at B3LYP/6-31+G(d) and then the dielectric effects of the surrounding and the solvent effects on the stability energies of Pyrazole and Pyrazoline molecules were discussed.

Aquaporins are integral membrane proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells. Aquaporins form tetramers in the cell membrane with each monomer acting as a water channel.In this research, the AQP4 tetramer was modeled from its PDB structure file, then, we have performed the intraction of aquaporin4 in different temperatures (298k, 300k, 302k, 304k, 306k, 308k and 310k) with OPLS and Amber force field in molecular mechanic (MM) method. The Total energy (Et), Potential energy (Ep) and Kinetic energy (Ek) in (Kcal/mol), were examined, with Amber and OPLS in force field in molecular mechanic (MM) method. In this investigation HyperChem professional release 7.01 was used for the quantum chemical calculations. We have performed geometry optimization and Monte Carlo simulation by this software.

The effects of halogens, fluorine, chlorine and bromine, on the stability and multiplicity of phenyl carbenes / silylenes/ germylenes structures are compared and contrasted at B3LYP/6-311++G** //B3LYP/6-31+G* level. The singlet-triplet energy gaps, DES-T , values for all the above species increase through fluorinated up, DES-Ts and DEHOMO–LUMOs support the stability of the singlet states inspite of their corresponding triplet states. The investigations reveal that F, Cl and Br stabilize singlet states more than their corresponding triplet states. The reactivity of the species is discussed in terms of nucleophilicity and electrophilicity. This detailed study offers new insights into the chemistry of these classes of carbenes / silylenes/ germylenes.