inhibitory effect of three benzothiazole derivatives (1, 3-benzothiazol-2-amine (bta), 6-methyl-1, 3-benzothiazol-2-amine (mbta) and 2-amino-1, 3-benzothiazole-6-thiol (tbta)) on corrosion of carbon steel has been studied using density functional theory (dft) method in gas and aqueous phases. quantum chemical parameters such as ehomo (highest occupied molecular orbital energy), elumo (lowest un...

Calculations based on density functional methods are carried out to investigate the effects of a variety of substituents (NMe2, OMe, Me, F, H, Cl, CN, NO2) on the Mulliken charges (QM) for Cα and N atoms of N-(4-Substituted benzylidene)-1-phenylmethanamine oxide using Hammett’s MSP and Taft’s DSP equations. The MSP and DSP correlations give normal substituent effect at Cα and N atom sites. This...

A new approach for performing Particle Mesh Ewald in ab initio quantum mechanical/molecular mechanical (QM/MM) simulations with extended atomic orbital basis sets is presented. The new approach, the Ambient-Potential Composite Ewald (CEw) method, does not perform the QM/MM interaction with Mulliken charges nor electrostatically fit charges. Instead the nuclei and electron density interact direc...

Molecular modelling is routinely employed to assign 3D structures to collision cross sections (CCSs) derived from ion mobility mass spectrometry experiments (IM-MS). The assignment of model structures to the experimental CCSs remains an ambiguous task, where one of several methods may be used to obtain a CCS from a given set of coordinates. The most reliable of the commonly used techniques, the...

A partial charge database was constructed for 117 molecules. The actual database contains Mulliken, natural population analysis, and stockholder atomic charges calculated from the HF/6-31G(d) or HF/6-311þG(2d,p) wavefuntions. The MP2/631G(d), B3LYP/6-31G(d), or HF/6-31G(d) equilibrium geometries were used for these calculations. The database also contains the corresponding total energies calcul...

Quantum chemical calculations have been performed to compute optimized molecular geometry, atomic charges and vibrational characteristics for 2-hydroxy-3-methoxy-N-(2-chloro-benzyl)-benzaldehyde-imine (C15H14O2NCl) in the ground state using restricted Hartree-Fock (RHF) and density functional theory (DFT) methods with 6-31+G** basis set. NBO analysis is also performed. The IR and Raman spectra ...

Theoretical calculations are performed to study Cr2O n (n 1⁄4 4 6) clusters. The sequential oxidation of these clusters tends to quench the spin configuration of the ground state. For Cr2O 6 , the bonding orbitals dominate the higher valence molecular orbitals leading to a very high value of electron detachment energy for the cluster. Calculations also find the symmetric and asymmetric stretchi...

The present study deals with the solvent effect on the electronic spectra of 2,4-dihydroxy-5fluoropyrimidine i.e, the effect of polar solvents are ethanol, methanol, and water has been studied on the electronic transitions of the title molecule both experimentally and theoretically. The homo lumo analysis has been studied. Theoretical calculations are made with the help of Gaussian 03 by using ...

Results of ab initio Hartree-Fock calculations for the SrTiO3 ~110! polar surface are discussed. We have calculated the surface energies, near-surface atomic displacements for four possible terminations ~TiO, Sr, and two kinds of O terminations! as well as Mulliken atomic charges and dipole moments of atoms characterizing their polarization, and the atomic bond populations. We predict a conside...