Journal of Physical and Theoretical Chemistry
Volume:9 Issue: 4, Winter 2013

In this research, the effect of catalyst type on the CNTs synthesis was investigated. The carbonnanotubes (CNTs) were produced on stainless steel substrates and two of catalyst with differentcharacteristics by using Thermal chemical vapor deposition (TCVD) method. The catalysts have theimportant role for the growth carbon nanotubes (CNTs). Acetylene gas (C2H2) diluted by NH3 wasused as the reaction gas as a source of carbon. The formation of carbon nanotube structures wereconfirmed by Raman spectroscopy and scanning electron microscopy (SEM) methods. It was foundthat 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 sizeon the properties. Through a careful analysis of the successive binding energies, second-orderdifference of energy and the highest occupied-lowest unoccupied molecular orbital energy gaps as afunction of cluster size, an odd-even alternative phenomenon has been observed. The results showthat 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- independentSchrodinger equation are presented that allows one to obtain accurate bound state eigen values andeigen 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 inmore details. For this purpose, we first reformulated the Shrodinger equation using dimensionlessvariables, the estimating the initial and final values of the reduced variable xr and the value ofintervals sr, and finally making use of Q-Basic or Spread Sheet computer programs to numericallysolved the equation. For each case, we drew the eigen functions versus the related reduced variablefor the corresponding energies. The harmonic oscillator, the Morse potential, and the H-atom radialSchrodinger equation, … were the examples considered for the method. The paper ended with acomparison of the result obtained by the numerical solutions with those obtained via the analyticalsolutions. The agreement between the results obtained by analytical solution method and numericalsolution for some Potential functions harmonic oscillator̕ Morse was represents the top Numerovmethod for numerical solution Schrodinger equation with different potentials energy.

The Density of State and the Natural Bond Orbital calculations were carried out to study theoxidation of CO on Au14 nano cluster through two different mechanisms and determining the bestmechanism 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 thehighest occupied molecular orbital and the lowest unoccupied molecular orbital and its role in theadsorption phenomenon.

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 coefficient, f± , of CdF2 in the solution upon the extended Debye-Hückel theory, the modelsolubility Product constant of the salt, Ksp(m)=4s3 f±3 was calculated .On the other hand we concludedthe equilibrium constant of ion pair formation , KIP, on the basis of Fuoss contact ion pair model andwe 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 mixedsolvent was evaluated at zero ionic strength upon the extrapolation method and the value of ion pairconcentration 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) basissets, 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 wasperformed for the ten solvents using PCM model method at B3LYP/6-31+G(d) and then the dielectriceffects of the surrounding and the solvent effects on the stability energies of Pyrazole and Pyrazolinemolecules were discussed.

Aquaporins are integral membrane proteins from a larger family of major intrinsic proteins that formpores in the membrane of biological cells. Aquaporins form tetramers in the cell membrane with eachmonomer acting as a water channel.In this research, the AQP4 tetramer was modeled from its PDBstructure 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 thisinvestigation 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 phenylcarbenes / silylenes/ germylenes structures are compared and contrasted at B3LYP/6-311++G**//B3LYP/6-31+G* level. The singlet-triplet energy gaps, ΔES-T , values for all the above speciesincrease through fluorinated up, ΔES-Ts and ΔEHOMO–LUMOs support the stability of the singlet statesinspite of their corresponding triplet states. The investigations reveal that F, Cl and Br stabilizesinglet states more than their corresponding triplet states. The reactivity of the species is discussed interms of nucleophilicity and electrophilicity. This detailed study offers new insights into thechemistry of these classes of carbenes / silylenes/ germylenes.