scholarly journals Analysis of the Kinetics and Yields of OH Radical Production from the CH3OCH2 + O2 Reaction in the Temperature Range 195–650 K: An Experimental and Computational study

2014 ◽  
Vol 118 (34) ◽  
pp. 6773-6788 ◽  
Author(s):  
A. J. Eskola ◽  
S. A. Carr ◽  
R. J. Shannon ◽  
B. Wang ◽  
M. A. Blitz ◽  
...  
Keyword(s):  
Computational Study ◽  
Oh Radical ◽  
Temperature Range ◽  
Radical Production

2-Deoxyribose Radicals in the Gas Phase and Aqueous Solution. Transient Intermediates of Hydrogen Atom Abstraction from 2-Deoxyribofuranose

2005 ◽  
Vol 70 (11) ◽  
pp. 1769-1786 ◽  
Author(s):  
Luc A. Vannier ◽  
Chunxiang Yao ◽  
František Tureček
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Gas Phase ◽  
Computational Study ◽  
Hydrogen Atom Abstraction ◽  
Oh Radical ◽  
Free Energies ◽  
Intramolecular Hydrogen ◽  
Solvation Free Energies ◽  
Transient Intermediates

A computational study at correlated levels of theory is reported to address the structures and energetics of transient radicals produced by hydrogen atom abstraction from C-1, C-2, C-3, C-4, C-5, O-1, O-3, and O-5 positions in 2-deoxyribofuranose in the gas phase and in aqueous solution. In general, the carbon-centered radicals are found to be thermodynamically and kinetically more stable than the oxygen-centered ones. The most stable gas-phase radical, 2-deoxyribofuranos-5-yl (5), is produced by H-atom abstraction from C-5 and stabilized by an intramolecular hydrogen bond between the O-5 hydroxy group and O-1. The order of radical stabilities is altered in aqueous solution due to different solvation free energies. These prefer conformers that lack intramolecular hydrogen bonds and expose O-H bonds to the solvent. Carbon-centered deoxyribose radicals can undergo competitive dissociations by loss of H atoms, OH radical, or by ring cleavages that all require threshold dissociation or transition state energies >100 kJ mol-1. This points to largely non-specific dissociations of 2-deoxyribose radicals when produced by exothermic hydrogen atom abstraction from the saccharide molecule. Oxygen-centered 2-deoxyribose radicals show only marginal thermodynamic and kinetic stability and are expected to readily fragment upon formation.

The reaction of O(3P) with alkynes: a dynamic and computational study focusing on formyl radical production

2020 ◽  
Vol 22 (42) ◽  
pp. 24583-24599
Author(s):  
Andrew D. Buettner ◽  
Benjamin J. Dilday ◽  
Rachel A. Craigmile ◽  
Matthew C. Drummer ◽  
Jean M. Standard ◽  
...  
Keyword(s):  
Computational Study ◽  
Formyl Radical ◽  
Radical Production

Experimental and computational study of the reaction of O(3P) with propyne, 1-butyne and 1-pentyne.

Computational study on the reaction of CH3SCH2CH3 with OH radical: mechanism and enthalpy of formation

2011 ◽  
Vol 129 (6) ◽  
pp. 771-780 ◽  
Author(s):  
Jia Cao ◽  
Wenliang Wang ◽  
Yue Zhang ◽  
Weina Wang ◽  
Tianlei Zhang ◽  
...  
Keyword(s):  
Enthalpy Of Formation ◽  
Computational Study ◽  
Radical Mechanism ◽  
Oh Radical

scholarly journals Blue to Yellow Photoluminescence Emission and Photocatalytic Activity of Nitrogen Doping in TiO2Powders

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Gabriela Byzynski ◽  
Caue Ribeiro ◽  
Elson Longo
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Oh Radical ◽  
Additional Energy ◽  
Photoluminescence Emission ◽  
Radical Production ◽  
N Doping ◽  
Band Gap Structure

The defects caused by doping are important for understanding the increased photocatalytic activities of TiO2:N in organic reactions and in the evaluation of OH radical production after doping. TiO2:N was therefore synthesized using a modified polymeric method and N doping was performed by calcination with urea. The resulting powders were characterized using field emission scanning electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, Raman spectroscopy, Fourier transformation infrared spectroscopy, and photoluminescence emission spectroscopy (PL). N doping did not alter the morphology of the nanoparticles, and the anatase phase predominated, with the retention of the rutile phase. The band gap values, superficial areas, and crystallite sizes of the powders decreased after doping. The PL results showed an additional energy level in the TiO2:N band gap structure as a result of TiO2lattice defects caused by doping. At low N contents, the powders showed continuous emissions from the blue region to the yellow region and a high N content shifted the PL emissions to the red region. These results suggest that the use of these powders could increase the efficiencies of solar cells and water-splitting processes. The photocatalytic activity of the powders under UVC illumination was confirmed for different organic dye molecules. The OH radical production did not change extensively after doping, as shown by experiments with terephthalic acid, and higher photocatalytic efficiencies in Rhodamine-B degradation under UVC illumination were achieved using the doped samples.

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