Quantum indistinguishability plays a crucial role in many low-energy physical phenomena, from quantum fluids to molecular spectroscopy. It is, however, typically ignored in most high temperature processes, particularly for ionic coordinates, implicitly assumed to be distinguishable, incoherent and thus well-approximated classically. We explore chemical reactions involving small symmetric molecu...

There are two different pictures of molecular structure: the classical and the quantummechanical. The classical picture is naive-empirical and is the chemical one; it is connected with classical structural formulae, ball-and-stick models, the phenomenological Lewis concept and the Gillespy rules for prediction of molecular geometry. This picture now endures as the heuristic instrument for the p...

Quantum chemical (MNDo)caleulations have beenused toelucidate the molecular properties and structure - activity relationships of dihydropyridine (DHP) type calcium antagonists. There is a good corielation between the net atomic charges on various atoms of the 4 - phenyl ring of dihydropyridines and pharmacological activity. .Also, activity decreases with increasing free rotation of the phen...

Nanopartmles have been used as an approach to improve the pharmacodynamic and phannacokinetie propertiesof various drues. Amino acids have been considered to be useful to make such nano particles because ofthocompatithe and biodegradable characteristic. The quantum mechanical method that was chosen to analyze inethio hexa peptide nano ring]. The structure of some peptide nanorrigs as well as th...

Based on the quantum chemical topology of modified electron localization function ELFx, an efficient and robust mechanistic methodology designed to identify favorable reaction pathway between two reactants is proposed. We first recall reshape how supermolecular interaction energy can be evaluated from only three distinct terms, namely intermolecular coulomb energy, exchange-correlation intramol...

In this study, the effect of fullerene electron mobility on the composition of paraphenylenediamine and stability was studied. Using quantum chemistry calculations, the first combination of paraffenylenediamine in a single-full-time region connected with fullerene through carbon atoms was reported. Experimental research was simulated and optimized using GIS software. Then the NBO calculations w...

In this research at the first Enalapril drug and its fullerene derivative were optimized. NBO calculations and NMR for the complexes were carried out at the B3LYP/6-31G* quantum chemistry level. Different parameters such as energy levels, the amount of Chemical Shift in different atoms, the amount of HOMO/LUMO, chemical potential (µ ), chemical hardness (η), the coefficients of hybrid bonds (π,...

In this research at the first 2-amino-3-(3,4-dihydroxyphenyl) propanoic aciddrug  drug and its fullerene derivative were optimized. NBO calculations and NMR for the complexes were carried out at the B3LYP/6-31G*quantum chemistry level. Different parameters such as energy levels, the amount of Chemical Shift in different atoms, the amount of HOMO/LUMO, chemical potential (µ ), chemical hardness ...

In this paper, quantum chemical parameters at density functional theory (DFT) B3LYP/6-31G** (d,p) level of theory were calculated for three organic corrosion inhibitors [N-benzoyl-N-(p-aminophenyl) thiourea, N-benzoyl-N-(thiazole) thiourea and N-acetyl-N-(dibenzyl) thiourea. The calculated molecular descriptors such as the HOMO, LUMO, dipole moment, chemical potential (μ), chemical hardness (ղ)...

ion molecules with general chemical formula as [li(h2o)] (n=1,2,3), have been chosen as model species toinvestigate the chemical properties of hydrated lithium cations. the rhf(scvs)/ugbs level of calculationhas been used for obtaining equilibrium geometries and rho(r) functions (electron density distributions). by theaid of fundamental physical theorems implemented in quantum theory of atoms i...