the n-(2-benzoyl-phenyl) oxalyl derivatives are important models for studying of three-centered intramolecular hydrogen bonding in organic molecules. the quantum theoretical calculations for two crystal structures of n-(2-benzoyl-phenyl) oxalyl (compounds i and ii) were performed by density functional theory (b3lyp method and 6-311+g* basis set). from the optimized structures, geometric paramet...

The structural and vibrational properties of 6-(2-(2,4-dinitrophenylhydrazano)-tetrahydro-2thioxopyrimidin-4(1H)-one (3) prepared by condensation of synthesized thiobarbituric acid (1) with 2,4-dinitrophenylhydrazine (2) were studied using experimental FT-IR, FT-Raman, NMR spectra and theoretical calculations based on the density functional method were the simulated spectra coincides with exper...

electronic effects were investigated on the singlet–triplet energy gaps of divalent unsaturated seven- membered ring r2c6h6m (m=c, si, ge, sn, pb, r= –h, -ch3, i-pr , t-bu) at b3lyp/6-311++g** level. all the triplet states of r2c6h6c were more stable than the related the singlet states while all the singlet states of r2c6h6m (m= si, ge, sn, pb, r= –h, -ch3, i-pr , t-bu) were more stable than th...

In the present work, the sensitivity to the moisture (hygroscopisity) is studied for 3,4-dinitropyrazole (DNP) as a famous energetic molecule. All of the DNP-H2O complex systems (1-3) as well as individual molecules were optimized and bond lengths, bond angles, dihedral angles, charge transfer and stability via NBO analysis, corrected interaction energies with ZPE + BSSE and hydrogen bonds anal...

A DFT study of the electronic properties of ansa-titanocene dichloride is reported. Molecular orbital analysis, polarizability, hyperpolarizability, thermodynamic analysis and natural bond orbital (NBO) theory are the main aim of the present research. The computed structural parameters show a good agreement with the similar experimental results. The calculated HOMO and LUMO energies show that c...

Most approximations to the exchange-correlation functional of Kohn-Sham density functional theory lead to delocalization errors that undermine the description of charge-transfer phenomena. We explore how various approximate functionals and charge-distribution schemes describe ground-state atomic-charge distributions in the lithium-benzene complex, a model system of relevance to carbon-based sup...

Oxaliplatinium is an anticancer drug, used in chemotherapy. To investigate the oxaliplatinium structure based on frontier orbital analysis, thermodynamic analysis and natural bond orbital (NBO) theory is the main objective of the present research. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The NBO charges, the values of electric dipole moment (µ) of ...

We present a comprehensive molecular dynamics (MD) simulation study of composition-structure trends in a set of 25 glasses of widely spanning compositions from the following four systems of increasing complexity: Na2O-B2O3, Na2O-B2O3-SiO2, Na2O-CaO-SiO2-P2O5, and Na2O-CaO-B2O3-SiO2-P2O5. The simulations involved new B-O and P-O potential parameters developed within the polarizable shell-model f...

First principles electronic structure calculations are typically performed in terms of molecular orbitals (or bands), providing a straightforward theoretical avenue for approximations of increasing sophistication, but do not usually provide any qualitative chemical information about the system. We can derive such information via post-processing using natural bond orbital (NBO) analysis, which p...