Molecular dynamics and Monte Carlo simulations have been performed for characterizing the structure of the 0.2 and 1 molar aqueous trimethylammonium chloride solutions. Atomic charges were derived through the CHELPG and RESP fits to the molecular electrostatic potentials calculated for the cation in water at the IEF-PCM/B3LYP level using the 6-31G* and 6-311++G** basis sets. Maxima and minima o...

using gaussian 03, software the thermodynamic functions such as gibbs free energy, g, enthalpy, h, and entropy, s, of alanine and valine amino acids were theoretically studied at different solvents. first, the density functional theory (b3lyp) level with 3-21g, 6-31g and 6-31+g basis sets were employed to optimization of isolated alanine and valine amino acids in the gas phase. moreover, vib...

Recently developed three-layer-mesh bridging domain method (TBDM) enhanced the conventional bridging domain method (BDM) by (1) mitigating the temperature cooling effect on the atoms in the bridging domain, and (2) employing a mesh-independent physics-based discrimination between thermal and mechanical atomic motions. In this paper, we present the new enhancements for the TBDM to achieve an app...

We study accommodation of an excess charge carrier on long even-N polyynic oligomers C(N)H(2) due to displacements of the underlying carbon lattice and polarization of the surrounding solvent in the context of carrier self-localization into a polaronic state. Spatial patterns of bond-length alternation, excess charge and spin densities are compared as derived with Hartree-Fock and two hybrid de...

The recent explosion1), 2) of research on the electronic properties of single layer and stacked multilayer graphene sheets has been driven by advances in material preparation methods,3), 4) by the unusual5), 6), 7) electronic properties of these materials including unusual quantum Hall effects,8), 9) and by hopes that these elegantly tunable systems might be useful electronic materials. In this...

A novel mechanism of SWNT nucleation is considered in oppose to an existing model. The latter model based on the formation of a hemispherical carbon bowl nucleus has no correct description within the thermodynamics and kinetics of the nucleation process. The new mechanism can explain the prevalent formation of [10,10] armchair nanotube on the base of the continuum graphene energetics.

In this research work, nano-phase change material (NPCM) composites were prepared by adding 1 %, 2 and 3 % mass fractions of highly conductive carbon-based graphene nanoparticles into the base phase (PCM). The existence uniform dispersion in PCM was confirmed through Raman spectrometer scanning electron microscope (SEM) analysis. Fourier transform infrared (FTIR) x-Ray diffraction (XRD) results...

Zone-boundary phonons are described in a valence-force-field model and then converted into a continuum model. Only a mode with the highest frequency corresponding to a Kekulé-type distortion gives rise to inter-valley electron scattering between K and K’ points. An effective Hamiltonian for this interaction is obtained and used for the estimation of inter-valley scattering in graphene and nanot...

Hydration of neutral and cationic imidazole is studied by means of ab initio and molecular dynamics calculations, and by photoelectron spectroscopy of the neutral species in a liquid microjet. The calculations show the importance of long range solvent polarization and of the difference between the structure of water molecules in the first shell around the neutral vs cationic species for determi...