A systematic approach has been adopted for structural analysis of Ranitidine Hydrochloride by using FTIR, FT Raman and UV-Vis and NMR spectroscopic techniques. The vibrational analysis are aided by electronic structure calculations HF method and density functional methods (B3LYP) performed with 6-31G(d,p) basis set, with the observed FTIR and FT Raman data, complete vibrational band assignments...

The capabilities and limitations of the Becke-3-Lee-Yang-Parr (B3LYP) hybrid density functional are investigated as applied to studies of mixed-valent multinuclear oxomanganese complexes. Benchmark calculations involve the analysis of structural, electronic and magnetic properties of di-, tri- and tetra-nuclear Mn complexes, previously characterized both chemically and spectroscopically, includ...

To calculation non-bonded interaction of the [CoCl6]3- complex embedded in nano ring, we focus on the single wall boron-nitride B18N18 nano ring. Thus, the geometry of B18N18 nano ring has been optimized by B3LYP method with EPR-II (Electron paramagnetic resonance) basis set and geometry of the [CoCl6]3- complex has been optimized at B3LYP method with Aldrich’s VTZ basis set and Stuttgart RSC 1...

In this study, the drug atenolol on C60 fullerene were the drug and its derivatives were optimized fullerene. NBO and NMR for complex computations required in the HF/6-31G (d) and B3LYP/6-31G (d) quantum chemistry method was used. Mechanical quantum calculations in theory level of B3LYP/6-31G were performed on structure of atenolol and nano fullerene atenolol with different positions...

ion of the tertiary hydrogen atom by peroxy group located at A-position, viz., IO-AQJ IO-AQCJ is the lowest energy process among the H-transfer reactions involving any isooctane peroxy radicals. The activation barrier ΔH (TS-C1A) is as low as ca.17 kcal mol (16.74, 17.09, 16.95 kcal mol, correspondingly, at B3LYP/6-31G(d), G3MP2B3, and CBS-QB3 levels of theory in agreement with the unified para...

Here, we apply the harmonic Fourier beads (HFB) path optimization method to study chemical reactions involving covalent bond breaking and forming on quantum mechanical (QM) and hybrid QM∕molecular mechanical (QM∕MM) potential energy surfaces. To improve efficiency of the path optimization on such computationally demanding potentials, we combined HFB with conjugate gradient (CG) optimization. Th...

In this work, regular convergence patterns of the structural, harmonic, and VPT2-calculated anharmonic vibrational parameters of ethylene towards the Kohn-Sham complete basis set (KS CBS) limit are demonstrated for the first time. The performance of the VPT2 scheme implemented using density functional theory (DFT-BLYP and DFT-B3LYP) in combination with two Pople basis sets (6-311++G** and 6-311...

The present work is related to predicting the pKa values of organosulfur compounds through density functional theory (DFT). In this study, 22 were considered calculate theoretical values. main emphasis was given on substitution different groups sulfur atom. computations performed in presence dimethyl sulfoxide (DMSO) as solvent. Experimentally, order increase acidity is; sulfides < sulfoxide...

In this study the hardness SWCT was calculated with B3LYP,HF method and 3-21G,6-31G,6-311G basis set .Then it was investigated with the best method(B3LYP) and basis set(6-31G) to study the adsorption effects CO2 on the hardness of SWCNT with gap HOMO-LUMO in two shape: Horizontal, Vertical and Top-Center-Bridge and We also provide the effects of CO2 adsorption on the elect...

Density functional theory has been gaining popularity for studying the radical scavenging activity of antioxidants. However, only a few studies investigate importance calculation methods on radical-scavenging reactions. In this study, we examined significance (i) long-range correction coulombic interaction and (ii) London dispersion to hydroperoxyl reaction trans-resveratrol gnetin C. We employ...