scholarly journals Dynamics of Singlet Oxygen Molecule Trapped in Silica Glass Studied by Luminescence Polarization Anisotropy and Density Functional Theory

2020 ◽  
Vol 124 (13) ◽  
pp. 7244-7253
Author(s):  
Linards Skuja ◽  
Krisjanis Smits ◽  
Anatoly Trukhin ◽  
Florian Gahbauer ◽  
Ruvin Ferber ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Singlet Oxygen ◽  
Silica Glass ◽  
Density Functional ◽  
Oxygen Molecule ◽  
Polarization Anisotropy ◽  
Functional Theory ◽  
Luminescence Polarization

The structure and activity of potassium supported on SBA-15 molecular sieve: Density functional theory study

2014 ◽  
Vol 13 (01) ◽  
pp. 1350076 ◽  
Author(s):  
Bing Liu ◽  
Daxi Wang ◽  
Zhongxue Wang ◽  
Zhen Zhao ◽  
Yu Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Lewis Acid ◽  
Molecular Sieve ◽  
Active Sites ◽  
Density Functional ◽  
Structural Model ◽  
Vibrational Frequencies ◽  
Oxygen Molecule ◽  
Lewis Base ◽  
Functional Theory

The geometries, vibrational frequencies, electronic properties and reactivity of potassium supported on SBA-15 have been theoretically investigated by the density functional theory (DFT) method. The structural model of the potassium supported on SBA-15 was constructed based on our previous work [Wang ZX, Wang DX, Zhao Z, Chen Y, Lan J, A DFT study of the structural units in SBA-15 mesoporous molecular sieve, Comput. Theor. Chem.963, 403, 2011]. This paper is the extension of our previous work. The most favored location of potassium atom was obtained by the calculation of substitution energy. The calculated vibrational frequencies of K /SBA-15 are in good agreement with the experimental results. By analyzing the properties of electronic structure, we found that the O atom of Si - O (2)- K group acts as the Lewis base center and the K atom acts as the Lewis acid center. The reactivity of K /SBA-15 was investigated by calculating the activation of oxygen molecule. The oxygen molecule can be activated by K /SBA-15 with an energy barrier of 103.2 kJ/mol. In the final state, the activated oxygen atoms become new Lewis acid centers, which are predicted to act as the active sites in the catalytic reactions. This study provides a deep insight into the properties of supported potassium catalysts and offers fundamental information for further research.

First-principles study of oxygen and hydrogen adsorption on Pt(111) and PtML/Pd(111) surfaces

2015 ◽  
Vol 29 (31) ◽  
pp. 1550199 ◽  
Author(s):  
J. L. Nie ◽  
L. Ao ◽  
X. T. Zu
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Chemical Interaction ◽  
Energy Difference ◽  
Covalent Bonding ◽  
Oxygen Molecule ◽  
First Principles Calculations ◽  
Functional Theory

In this paper, first-principles calculations based on density functional theory (DFT) have been performed to investigate the adsorption of oxygen and hydrogen on [Formula: see text] and [Formula: see text] surfaces covered by monolayer (ML) of [Formula: see text]. The results have shown that the oxygen molecule tends to adsorb on fcc site on both surfaces at the coverage of 0.25 ML, which becomes degeneration with hcp site when the coverage increases to 1 ML. For both oxygen and hydrogen, the adsorption on [Formula: see text] surface are stronger than those on [Formula: see text] surface. The adsorption energy difference for oxygen on the two surfaces is [Formula: see text][Formula: see text]0.2 eV at the coverage of 1 ML, which increases to [Formula: see text][Formula: see text]0.6 eV with the coverage decreasing to 0.25 ML. The similar energy difference was also found for hydrogen adsorption. The density of states analysis have demonstrated the chemical interaction of adsorbed oxygen with both pure [Formula: see text] and [Formula: see text] surfaces with certain shift of [Formula: see text] states to lower level compared to isolated oxygen. For hydrogen adsorption, the hybridization of [Formula: see text] with [Formula: see text] states were observed for both surfaces, indicating the covalent bonding component of H–Pt bond.

DFT Calculation for Oxidation Reaction of SiC(0001)

2019 ◽  
Vol 963 ◽  
pp. 208-212
Author(s):  
Tomoya Ono
Keyword(s):  
Density Functional Theory ◽  
Oxidation Reaction ◽  
Density Functional ◽  
Dft Calculation ◽  
Density Functional Theory Calculation ◽  
Oxygen Molecule ◽  
Functional Theory ◽  
Theory Calculation

The reaction-limiting process for the oxidation of SiC(0001) was investigated by density functional theory calculation. I found that the oxygen molecule insertion to the interfacial SiC bonds is the limiting process and the barrier is 3.21 eV. It is also found that the CO detachment is not limiting process because the barrier becomes small when the interfacial C atom is surrounded by three O atoms.

Negligible Ability of Oxygen and Peroxide Ion Activation by Al(III) Ion Is Essential for Al(III)-Induced Neurodegeneration

2001 ◽  
Vol 56 (9-10) ◽  
pp. 865-871 ◽  
Author(s):  
Yuzo Nishida
Keyword(s):  
Density Functional Theory ◽  
Tyrosine Hydroxylase ◽  
Aromatic Ring ◽  
Density Functional ◽  
Density Functional Theory Method ◽  
Oxygen Molecule ◽  
Theory Method ◽  
Functional Theory ◽  
Previous Proposal ◽  
Electron Donation

Abstract The electron densities of the atoms in Fe(II)-or Al(III)-tyrosine hydroxylase (THO) containing oxygen and pterin were calculated by the DFT (Density-functional theory) method. The results obtained are consistent with our previous proposal that oxygen activation in THO proceeds through the formation of an intermediate derived from Fe(II), oxygen, and pterin. Electron donation from substrate to the oxygen molecule is important to cleave the O-O bond, and to give the hydroxylated product. Based on these results, it was concluded that hydroxylation of the aromatic ring does not proceed in the Al(III)-containing THO, and a relationship exists between Al(III) ion and neurodegeneration.

scholarly journals Practical treatment of singlet oxygen with density-functional theory and the multiplet-sum method

2021 ◽  
Vol 140 (11) ◽  
Author(s):  
Abraham Ponra ◽  
Anne Justine Etindele ◽  
Ousmanou Motapon ◽  
Mark E. Casida
Keyword(s):  
Density Functional Theory ◽  
Singlet Oxygen ◽  
Density Functional ◽  
Functional Theory

Doping effects on the geometric and electronic structure of tin clusters

2019 ◽  
Vol 21 (44) ◽  
pp. 24478-24488 ◽  
Author(s):  
Martin Gleditzsch ◽  
Marc Jäger ◽  
Lukáš F. Pašteka ◽  
Armin Shayeghi ◽  
Rolf Schäfer
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Beam Deflection ◽  
Functional Theory ◽  
Doping Effects ◽  
Depth Analysis ◽  
Trajectory Simulations

In depth analysis of doping effects on the geometric and electronic structure of tin clusters via electric beam deflection, numerical trajectory simulations and density functional theory.

What correlation effects are covered by density functional theory?

2000 ◽  
Vol 98 (20) ◽  
pp. 1639-1658 ◽  
Author(s):  
Yuan He, Jurgen Grafenstein, Elfi Kraka,
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Correlation Effects ◽  
Functional Theory
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