Main chain torsions of alanine dipeptide are parameterized into coupled 2-dimensional Fourier expansions based on quantum mechanical (QM) calculations at M06 2X/aug-cc-pvtz//HF/6-31G** level. Solvation effect is considered by employing polarizable continuum model. Utilization of the M06 2X functional leads to precise potential energy surface that is comparable to or even better than MP2 level, ...

The hydrogen abstraction reaction of OH radical with CH3CH2OCF2CHF2 (HFE-374pc2) is investigated theoretically by semi-classical transition state theory. The stationary points on the potential energy surface of the reaction are located by using KMLYP density functional method along with 6-311++G(d,p) basis set. Vibrational anharmonicity coefficients, ...

The monitoring and controlling of environmental pollutions are very important in biological and industrial processes, and a great interest is growing with the development of suitable gas–sensitive materials and hazardous chemical removal devices. In this work, the highly parameterized, empirical exchange–correlation functional M06–2X were employed to investigate the electronic sensitivity of pe...

Abstract We report a computational and experimental study of the reaction oxadiazinones strained alkynes to give polycyclic aromatic hydrocarbons (PAHs). The proceeds by way pericyclic cascade leads formation four new carbon−carbon bonds. Using M06‐2X DFT calculations, we interrogate several mechanistic aspects reaction, such as why use non‐aromatic can be used access unsymmetrical PAHs, wherea...

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...

the hydrogen abstraction reaction of oh radical with ch3ch2ocf2chf2 (hfe-374pc2) is investigated theoretically by semi-classical transition state theory. the stationary points on the potential energy surface of the reaction are located by using kmlyp density functional method along with 6-311++g(d,p) basis set. vibrational anharmonicity coefficients, xij, required for semi-classical transition ...

antioxidants are made for the struggle and reconstruction of the damaged cells, because of their ability in destroying the free radicals. on account of their importance, a theoretical procedure was applied for the study of the molecular structure and radical scavenging activity of six hydroxyphenols which have been introduced as antioxidant compounds. all geometry structures were optimized by m...

This study explores the degree to which GGA, meta-GGA, hybrid GGA, and hybrid meta-GGA functionals of density functional theory (DFT), when used with the 6-31+G(d) basis set, are able to reproduce the MP2/6-31+G(d) structures and energetics of the species involved in the reactions of halomethyllithium carbenoids with ethylene. While many popular DFT functionals have been parametrized and/or ben...

Accurate MP2 and CCSD(T) complete basis set (CBS) interaction energy curves (14 points for each curve) have been obtained for 20 of the dimers reported in the S22 set and analytical Morse curves have been fitted that can be used in developing updated density functional theory (DFT) and force field models. The magnitude and the effect of the basis set superposition error (BSSE) were carefully in...

The performance of 24 density functionals, including 14 meta-generalized gradient approximation (mGGA) functionals, is assessed for the calculation of vertical excitation energies against an experimental benchmark set comprising 14 small- to medium-sized compounds with 101 total excited states. The experimental benchmark set consists of singlet, triplet, valence, and Rydberg excited states. The...