نتایج جستجو برای: m06 2x

تعداد نتایج: 3641  

2013
S. Peukert R. Sivaramakrishnan

The shock tube technique was used to study the high temperature thermal decomposition of dimethyl carbonate, CH3OC(O)OCH3 (DMC). The formation of H-atoms was measured behind reflected shock waves by using atomic resonance absorption spectrometry (ARAS) over a temperature range of 1053–1157 K at pressures ~ 0.5 bar. The measured formation of H-atoms is sensitive to the rate constants for the ene...

Journal: :Physical chemistry chemical physics : PCCP 2011
Demeter Tzeli Ioannis D Petsalakis Giannoula Theodorakopoulos

The present work is a theoretical investigation on supramolecular complexes of a fullerene crown ether (A and B isomers) with a derivative of π-extended tetrathiafulvalene (T). The geometry and the electronic structure of seven different conformers of the complex of dibenzo-18-crown-6 ether of fullero-N-methylpyrrolidine with a N-benzyl-N-(4-{[9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthrac...

2014
Shi Liu Sriraj Srinivasan Michael C. Grady Masoud Soroush Andrew M. Rappe

Multiple mechanisms of backbiting and b-scission reactions in free-radical polymerization of methyl acrylate are modeled using different levels of theory, and the rigid-rotor harmonicoscillator (RRHO) and hindered-rotor (HR) approximations. We identify the most cost-effective computational method(s) for studying the reactions and assess the effects of different factors (e.g., functional type an...

2011
Vanessa Riffet Gilles Frison Guy Bouchoux

Acid–base thermochemistry of isolated amino acids containing oxygen or sulfur in their side chain (serine, threonine, cysteine and methionine) have been examined by quantum chemical computations. Density functional theory (DFT) was used, with B3LYP, B97-D and M06-2X functionals using the 6-31+G(d,p) basis set for geometry optimizations and the larger 6-311++G(3df,2p) basis set for energy comput...

2016
Hongyan Sun Ghanshyam L. Vaghjiani

Mononitrobiuret (MNB) and 1,5-Dinitrobiuret (DNB) are, tetrazole-free, nitrogen-rich, energetic compounds. For the first time, the thermal decomposition mechanisms of MNB and DNB have been investigated by advanced ab initio kinetics theories. In particular, the intramolecular interactions of amine H-atom with electronegative nitro O-atom and carbonyl O-atom have been analyzed for MNB, DNB, and ...

Journal: :Inorganics (Basel) 2023

This report deals with the quantum-chemical evaluation of energetics and thermodynamics simultaneous encapsulation HF H2O by IPR (isolated pentagon rule) C70 fullerene cage, yielding H2O·HF@C70 species which were synthesized characterized recently, thus further expanding family endohedrals non-metallic encapsulates. The structures optimized at DFT (density functional theory) M06-2X/6-31++G** le...

Journal: :Physical chemistry chemical physics : PCCP 2012
Isabella A Lobo David J D Wilson Evan Bieske Evan G Robertson

The neurotransmitter analogue p-aminophenethylamine (APEA) illustrates many of the pitfalls and challenges associated with spectroscopic and conformational analysis of flexible molecules. The combined experimental-theoretical study presented here resolves a long-standing controversy over its conformational energetic preferences. Jet-cooled resonance enhanced two-photon ionisation (R2PI) and IR-...

2010
Dennis Gerbig David Ley Hans Peter Reisenauer Peter R Schreiner

The first C-H insertion of a hydroxycarbene species in the gas phase has been observed experimentally by means of high vacuum flash pyrolysis (HVFP) and subsequent matrix isolation: (o-Methoxyphenyl)glyoxylic acid gives non-isolable (o-methoxyphenyl)hydroxycarbene upon pyrolysis at 600 °C, which rapidly inserts into the methyl C-H bond. The insertion product, 2,3-dihydrobenzofuran-3-ol, was tra...

Journal: :The journal of physical chemistry. A 2013
Nazanin Moghadam Shi Liu Sriraj Srinivasan Michael C Grady Masoud Soroush Andrew M Rappe

This article presents a computational study of chain transfer to monomer (CTM) reactions in self-initiated high-temperature homopolymerization of alkyl acrylates (methyl, ethyl, and n-butyl acrylate). Several mechanisms of CTM are studied. The effects of the length of live polymer chains and the type of monoradical that initiated the live polymer chains on the energy barriers and rate constants...

Journal: :Physical chemistry chemical physics : PCCP 2011
Vanessa Riffet Gilles Frison Guy Bouchoux

Acid-base thermochemistry of isolated amino acids containing oxygen or sulfur in their side chain (serine, threonine, cysteine and methionine) have been examined by quantum chemical computations. Density functional theory (DFT) was used, with B3LYP, B97-D and M06-2X functionals using the 6-31+G(d,p) basis set for geometry optimizations and the larger 6-311++G(3df,2p) basis set for energy comput...

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