The density functional theory (DFT) method combined with B3LYP and B3PW91 hybrid were utilized for geometrical optimization, vibrational frequencies electronic spectral study. levels of the time dependent-DFT 6–311+G(d, p) basis set have been used to determine highest occupied molecular orbital (HOMO) – lowest unoccupied (LUMO) energies, absorption wavelengths, properties (total energy gap) 4-(...

BACKGROUND Cyanoform is long known as one of the strongest acid. Cyanoform is only stable below -40 °C. The issue of the stability and tautomeric equilibria of cyanoform (CF) are investigated at the DFT and MP2 levels of theory. The present work presents a detailed study of structural tautomer interconversion in three different media, namely, in the gas phase, in a solvent continuum, and in a m...

Quantum chemistry calculations have been performed to compute optimized geometry, Mulliken charges, harmonic vibrational frequency along with intensities in IR at HF/6-311++G(d,p) and B3LYP/6-311++G(d,p) level for N-(1,3,4-thiadiazol-2-yl)-1-[1-(6-chloropyridin-3-yl)methy]-5-methyl-1-H-[1,2,3]triazol-4-carboxamide (C12H10ClN7OS) in the ground state. Theoretical vibrational spectra of the title ...

Raman and FTIR spectra of nicotinic acid have been analysed using ab-initio and DFT calculations. Four stable structures were found for nicotinic acid, the structures differ in orientation of COOH with respect to the nitrogen atom. The optimized geometries, harmonic vibrational wave number, structural parameters and intensities of the nicotinic acid have been calculated using MP2/6-311++G(d,p),...

We have calculated position and dot intracules for a series of atomic and molecular systems, starting from an unrestricted Hartree-Fock wave function, expanded using the STO-3G, 6-31G, 6-311G, 6-311++G, 6-311++G(d,p), 6-311++G(3d,3p), and 6-311++G(3df,3pd) basis sets as well as the nonpolarized part of Dunning's cc-pV5Z basis. We find that the basis set effects on the intracules are small and t...

The potential energy curves (PEC) of 2 Chalcone (E)-3-(Furan-2-yl)-1-Phenylprop-2-en-1-one (1) were calculated as a function dihedral angle φ(C8-C9-C10-O1) at both ab initio Hartree–Fock (HF) and Density Functional Theory (DFT) using the B3LYP functional together with 6-311++G (d,p) basis set syn- anti-conformers corresponding low conformers determined. optimized molecular structures, vibration...

The hydrogen bonding interaction in the Sarcosine (N-methylglycine)– water complex is studied using ab initio, MP2, and density functional theory (DFT/B3LYP). For this complex, binding energies, dipole–dipole interactions, chemical hardness, and chemical potential have been calculated. Three different basis sets, viz. 6-311 G, 6-311 G, and 6-311 G*, have been used to optimize the geometries by ...

The intermolecular forces between water molecules are of great importance in many areas of chemistry including solvation, solution chemistry, and biochemistry. As a result of this (H2O)n systems have received a great significant of attention, both experimental and theoretical. All calculation of this study are carried out by Gaussian 98 soft ware. Geometry optimization for each cluster were be ...