A theoretical study at the B3LYP/6-31++G(d,p) level was performed on the tatumerization of 7H-purine-2, 6-diamine into 9H-purine-2, 6-diamine. Such a tautomerism can take place via three different pathways namely A, B, and C. The energetic results associated with the gas phase reveal that pathways A, B, and C display a very high activation Gibbs free energy of 45.1, 68.6 and 48.9 kcal/mol, resp...

The Michelsen stability and multiphase flash calculation by direct minimization of Gibbs free energy of the system at constant temperature and pressure, was used for systems containing gas hydrates. The solid hydrate phase was treated as a solid solution. The fugacities of all components of the hydrate phase were calculated as a function of compositions by the rearranged model of van der Wa...

the michelsen stability and multiphase flash calculation by direct minimization of gibbs free energy of the system at constant temperature and pressure, was used for systems containing gas hydrates. the solid hydrate phase was treated as a solid solution. the fugacities of all components of the hydrate phase were calculated as a function of compositions by the rearranged model of van der waals ...

The Gibbs free energy of solvation and dissociation of hydrogen chloride in water is calculated through a combined molecular simulation/quantum chemical approach at four temperatures between T = 300 and 450 K. The Gibbs free energy is first decomposed into the sum of two components: the Gibbs free energy of transfer of molecular HCl from the vapor to the aqueous liquid phase and the standard-st...

chemical denaturation and thermal denaturation of13-lactoglobulin a (f3 — lga) in the absenceand presence of various concentrations sugar osmolytes and polyols were measured bymonitoring changes in the absorption coefficients at ph 2.0. it has been observed that agd°(h20), (gibbs free energy change in absence of denaturant at 25 °c) of f3-1ga in the presenceof 10% (w/v) trehalose, sucrose, sorb...

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...

the reaction of ch₃nh₂ with o₂ on the singlet potential energy surfaces (pes) was carried out using the b3lyp, ccsd(t) and g3b3 theoretical approaches along with 6-311++g(3df,3pd) basis set. the suggested mechanism for the title reaction consists of one pre-reactive complex. from the pre-reactive complex, nine types of products, ch2nh+h2o2, ch3nh+ooh, nh2cho+h2o, ch2nho+h2o, nh3+hcooh, ch2nh+h2...

biological materials. recently. are the building blocks of several self-assembling peptide and protein systems.the main challenge in molecular self-assembly is to design molecular building blocks that can undergospontaneous organization. these cyche peptides were produced by an alternating fl'ell number of d- and laminoacids.which interact through non-covalent interactions co an array of selfas...

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...