Theoretical H + O3 rate coefficients from ring polymer molecular dynamics on an accurate global potential energy surface: Assessing experimental uncertainties

2020 ◽  
Author(s):  
Qixin Chen ◽  
Xixi Hu ◽  
Hua Guo ◽  
Daiqian Xie
Keyword(s):  
Neural Network ◽  
Energy Surface ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Rate Coefficients ◽  
Invariant Polynomial ◽  
Kinetic Isotope ◽  
Polynomial Neural Network ◽  
Ring Polymer ◽  
Atmospheric Reaction

Thermal rate coefficients and kinetic isotope effects have been calculated for an important atmospheric reaction H/D + O3 → OH/OD + O2 based on an accurate permutation invariant polynomial-neural network...

scholarly journals Rate Coefficients and Kinetic Isotope Effects of the Cl + XCl  XCl + Cl (X=H, D, Mu) Reactions from Ring Polymer Molecular Dynamics

2020 ◽  
Author(s):  
junhua fang ◽  
Wenbin Fan ◽  
Hui Yang ◽  
Jianing Song ◽  
Yongle Li
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Energy Surface ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Rate Coefficients ◽  
Theoretical Methods ◽  
Kinetic Isotope ◽  
Ring Polymer ◽  
Experimental Values

<p>The ring-polymer molecular dynamics (RPMD) was used to calculate the thermal rate coefficients and kinetic isotope effects of the heavy-light-heavy abstract reaction Cl + XCl ® XCl + Cl (X=H, D, Mu). For the Cl + HCl reaction, the excellent agreement between the RPMD and experimental values provides a strong proof for the accuracy of the RPMD theory. And the RPMD results also consistent with results from other theoretical methods including improved-canonical-variational-theory and quantum dynamics. The most novel finding is there is a double peak in Cl + MuCl reaction near the transition state, leaving a free energy well. It comes from the mode softening of the reaction system at the peak of the potential energy surface. Such an explicit free energy well suggests strongly there is an observable resonance. And for the Cl + DCl reaction, the RPMD rate coefficient again gives very accurate results comparing with experimental values. The only exception is at the temperature of 312.5 K, at this temperature, results from RPMD and all other theoretical methods are close to each other but slightly lower than the experimental value, which indicates experimental or potential energy surface deficiency.</p><div><br></div>

scholarly journals Rate Coefficients and Kinetic Isotope Effects of the XCl + Cl (X=H, D, Mu) Reactions from Ring Polymer Molecular Dynamics

2020 ◽  
Author(s):  
junhua fang ◽  
Wenbin Fan ◽  
Hui Yang ◽  
Jianing Song ◽  
Yongle Li
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Energy Surface ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Rate Coefficients ◽  
Theoretical Methods ◽  
Kinetic Isotope ◽  
Ring Polymer ◽  
Experimental Values

<p>The ring-polymer molecular dynamics (RPMD) was used to calculate the thermal rate coefficients and kinetic isotope effects of the heavy-light-heavy abstract reaction Cl + XCl ® XCl + Cl (X=H, D, Mu). For the Cl + HCl reaction, the excellent agreement between the RPMD and experimental values provides a strong proof for the accuracy of the RPMD theory. And the RPMD results also consistent with results from other theoretical methods including improved-canonical-variational-theory and quantum dynamics. The most novel finding is there is a double peak in Cl + MuCl reaction near the transition state, leaving a free energy well. It comes from the mode softening of the reaction system at the peak of the potential energy surface. Such an explicit free energy well suggests strongly there is an observable resonance. And for the Cl + DCl reaction, the RPMD rate coefficient again gives very accurate results comparing with experimental values. The only exception is at the temperature of 312.5 K, at this temperature, results from RPMD and all other theoretical methods are close to each other but slightly lower than the experimental value, which indicates experimental or potential energy surface deficiency.</p><div><br></div>

Rate Coefficients and Kinetic Isotope Effects of the XCl + Cl (X=H, D, Mu) Reactions from Ring Polymer Molecular Dynamics

2020 ◽  
Author(s):  
junhua fang ◽  
Wenbin Fan ◽  
Hui Yang ◽  
Jianing Song ◽  
Yongle Li
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Energy Surface ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Rate Coefficients ◽  
Theoretical Methods ◽  
Kinetic Isotope ◽  
Ring Polymer ◽  
Experimental Values

<p>The ring-polymer molecular dynamics (RPMD) was used to calculate the thermal rate coefficients and kinetic isotope effects of the heavy-light-heavy abstract reaction Cl + XCl ® XCl + Cl (X=H, D, Mu). For the Cl + HCl reaction, the excellent agreement between the RPMD and experimental values provides a strong proof for the accuracy of the RPMD theory. And the RPMD results also consistent with results from other theoretical methods including improved-canonical-variational-theory and quantum dynamics. The most novel finding is there is a double peak in Cl + MuCl reaction near the transition state, leaving a free energy well. It comes from the mode softening of the reaction system at the peak of the potential energy surface. Such an explicit free energy well suggests strongly there is an observable resonance. And for the Cl + DCl reaction, the RPMD rate coefficient again gives very accurate results comparing with experimental values. The only exception is at the temperature of 312.5 K, at this temperature, results from RPMD and all other theoretical methods are close to each other but slightly lower than the experimental value, which indicates experimental or potential energy surface deficiency.</p><div><br></div>

scholarly journals Rate Coefficients and Kinetic Isotope Effects of the XCl + Cl (X=H, D, Mu) Reactions from Ring Polymer Molecular Dynamics

2020 ◽  
Author(s):  
junhua fang ◽  
Wenbin Fan ◽  
Hui Yang ◽  
Jianing Song ◽  
Yongle Li
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Energy Surface ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Rate Coefficients ◽  
Theoretical Methods ◽  
Kinetic Isotope ◽  
Ring Polymer ◽  
Experimental Values

<p>The ring-polymer molecular dynamics (RPMD) was used to calculate the thermal rate coefficients and kinetic isotope effects of the heavy-light-heavy abstract reaction Cl + XCl ® XCl + Cl (X=H, D, Mu). For the Cl + HCl reaction, the excellent agreement between the RPMD and experimental values provides a strong proof for the accuracy of the RPMD theory. And the RPMD results also consistent with results from other theoretical methods including improved-canonical-variational-theory and quantum dynamics. The most novel finding is there is a double peak in Cl + MuCl reaction near the transition state, leaving a free energy well. It comes from the mode softening of the reaction system at the peak of the potential energy surface. Such an explicit free energy well suggests strongly there is an observable resonance. And for the Cl + DCl reaction, the RPMD rate coefficient again gives very accurate results comparing with experimental values. The only exception is at the temperature of 312.5 K, at this temperature, results from RPMD and all other theoretical methods are close to each other but slightly lower than the experimental value, which indicates experimental or potential energy surface deficiency.</p><div><br></div>

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