scholarly journals Theoretical Mechanism Study on the Reaction of FOO Radical with NO

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
ShunLi Ou Yang ◽  
NanNan Wu ◽  
JingYao Liu ◽  
XiangGang Han
Keyword(s):  
Electronic Structure ◽  
Potential Energy Surfaces ◽  
Room Temperature ◽  
Single Point ◽  
Deep Insight ◽  
Mechanism Study ◽  
Structure Information ◽  
Theoretical Mechanism ◽  
Energy Surfaces ◽  
Insight Into

The mechanism for the reaction of radical FOO with NO was investigated theoretically. The electronic structure information for the singlet potential energy surfaces (PES) was obtained at the MP2/6-311+G(2df) level of theory, and the single-point energies were refined by the CCSD(T)/6-311+G(2df) level. The rate constants as well as the pressure and temperature dependence of various product channels for the reaction are predicted. The calculated results show that starting from the energy-rich intermediateFOONOtp(IM1), at room temperature 298 K and at 1 Torr, FNO is the exclusive product which is consistent with the experimental results. The present results will be useful to gain a deep insight into the reaction mechanism of FOO + NO reaction.

scholarly journals Energy, orbital and structural stacking landscape of a purine homodimer system

2020 ◽  
Vol 139 (10) ◽  
Author(s):  
Tomasz Sierański
Keyword(s):  
Potential Energy ◽  
Intermolecular Interactions ◽  
Potential Energy Surfaces ◽  
Natural Bond Orbital ◽  
Natural Bond Orbital Analysis ◽  
Energy Sources ◽  
Energy Decomposition ◽  
Energy Surfaces ◽  
Orbital Analysis ◽  
Insight Into

Abstract The multidimensional study, combining the extensive calculations of potential energy surfaces for the parallel-displaced configurations and methods such as energy decomposition and natural bond orbital analysis, has been carried out. The resulted data give an energy, orbital and structural landscapes of this biologically essential system. The balance of the two energy sources, electrostatic and dispersion, is clearly visible. The obtained results, taken as a whole, provide an insight into the hierarchy of intermolecular interactions in the purine system, together with their sources.

scholarly journals De novo exploration and self-guided learning of potential-energy surfaces

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Noam Bernstein ◽  
Gábor Csányi ◽  
Volker L. Deringer
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Materials Science ◽  
De Novo ◽  
Interatomic Potential ◽  
Single Point ◽  
Small Unit ◽  
Wide Range ◽  
Unit Cells ◽  
Energy Surfaces

Abstract Interatomic potential models based on machine learning (ML) are rapidly developing as tools for material simulations. However, because of their flexibility, they require large fitting databases that are normally created with substantial manual selection and tuning of reference configurations. Here, we show that ML potentials can be built in a largely automated fashion, exploring and fitting potential-energy surfaces from the beginning (de novo) within one and the same protocol. The key enabling step is the use of a configuration-averaged kernel metric that allows one to select the few most relevant and diverse structures at each step. The resulting potentials are accurate and robust for the wide range of configurations that occur during structure searching, despite only requiring a relatively small number of single-point DFT calculations on small unit cells. We apply the method to materials with diverse chemical nature and coordination environments, marking an important step toward the more routine application of ML potentials in physics, chemistry, and materials science.

scholarly journals Photodissociation of the CH3O and CH3S radical molecules: an ab initio electronic structure study

2017 ◽  
Vol 19 (46) ◽  
pp. 31245-31254 ◽  
Author(s):  
A. Bouallagui ◽  
A. Zanchet ◽  
O. Yazidi ◽  
N. Jaïdane ◽  
L. Bañares ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Potential Energy ◽  
Ab Initio ◽  
Potential Energy Surfaces ◽  
Structure Study ◽  
Spin Orbit ◽  
Energy Surfaces ◽  
Ab Initio Electronic Structure

Potential-energy surfaces and spin–orbit couplings involved in the photodissociation of the CH3O and CH3S radicals have been investigated.

Theoretical study on the chemical formation mechanism of a β-myrcene ozonolysis reaction under atmospheric conditions

2012 ◽  
Vol 90 (8) ◽  
pp. 708-715 ◽  
Author(s):  
Yuyang Zhao ◽  
Jing Bai ◽  
Chenxi Zhang ◽  
Chen Gong ◽  
Xiaomin Sun
Keyword(s):  
Rate Constants ◽  
Potential Energy Surfaces ◽  
Density Functional ◽  
Single Point ◽  
State Theory ◽  
Tunneling Effect ◽  
Atmospheric Conditions ◽  
Functional Theory ◽  
Real Atmosphere ◽  
Energy Surfaces

Density functional theory (DFT) was used to study the β-myrcene ozonolysis reaction. The reactants, intermediates, transition states, and products were optimized at the MPWB1K/6–31G(d,p) level. The single-point energies were performed at the MPWB1K/6–311+G(3df,2p) level. The profiles of the potential energy surfaces were constructed and the rate constants of the reaction steps were analyzed. The possible reaction mechanisms for the ozonolysis intermediates in real atmosphere are also discussed. Based on quantum chemistry information, the rate constants were calculated using Rice–Ramsperger–Kassel–Marcus (RRKM) theory and the canonical variational transition-state theory (CVT) with small curvature tunneling effect (SCT). Arrhenius equations of rate constants over the temperature range of 200–800 K are provided, and the lifetimes of the reaction species in the troposphere were estimated according to rate constants.

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