Communication: Prediction of the rate constant of bimolecular hydrogen exchange in the water dimer using an ab initio potential energy surface

2010 ◽  
Vol 133 (11) ◽  
pp. 111103 ◽  
Author(s):  
Yimin Wang ◽  
Joel M. Bowman ◽  
Xinchuan Huang
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Rate Constant ◽  
Hydrogen Exchange ◽  
Energy Surface ◽  
Water Dimer

scholarly journals Rate constant calculations of the GeH4 + OH/OD → GeH3 + H2O/HOD reactions using an ab initio based full-dimensional potential energy surface

2016 ◽  
Vol 18 (25) ◽  
pp. 16941-16949 ◽  
Author(s):  
J. Espinosa-Garcia ◽  
C. Rangel ◽  
J. C. Corchado
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Saddle Point ◽  
Ab Initio ◽  
Rate Constant ◽  
Energy Surface ◽  
Entry And Exit ◽  
Analytical Potential

2D representation of the analytical potential energy surface. The saddle point and the complexes in the entry and exit channels are included.

THE RATE CONSTANT OF THE O(3P) + HCl → OH + Cl REACTION WITHIN QUANTUM INSTANTON APPROXIMATION

2012 ◽  
Vol 11 (01) ◽  
pp. 143-153 ◽  
Author(s):  
MARCIN BUCHOWIECKI
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Temperature Dependence ◽  
Exchange Reaction ◽  
Rate Constant ◽  
Present Method ◽  
Hydrogen Exchange ◽  
Energy Surface ◽  
Arrhenius Plot ◽  
Quantum Instanton

Temperature dependence of the rate constant of the O (3 P ) + HCl → OH + Cl reaction was calculated for 200–700 K range within the quantum instanton approximation using the 3A″ potential energy surface. Curvature of the Arrhenius plot arising from quantum effects in the hydrogen exchange reaction was observed. Results of the present method were found to significantly improve upon those obtained within the ICVT/μOMT method. The errors pertaining to the present method were estimated.

Active Learning Accelerates Ab Initio Molecular Dynamics on Pericyclic Reactive Energy Surfaces

2020 ◽  
Author(s):  
Shi Jun Ang ◽  
Wujie Wang ◽  
Daniel Schwalbe-Koda ◽  
Simon Axelrod ◽  
Rafael Gomez-Bombarelli
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Transition State ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Energy Surface ◽  
Computational Cost ◽  
Reactive Trajectories ◽  
Dynamics Simulations ◽  
Energy Surfaces

<div>Modeling dynamical effects in chemical reactions, such as post-transition state bifurcation, requires <i>ab initio</i> molecular dynamics simulations due to the breakdown of simpler static models like transition state theory. However, these simulations tend to be restricted to lower-accuracy electronic structure methods and scarce sampling because of their high computational cost. Here, we report the use of statistical learning to accelerate reactive molecular dynamics simulations by combining high-throughput ab initio calculations, graph-convolution interatomic potentials and active learning. This pipeline was demonstrated on an ambimodal trispericyclic reaction involving 8,8-dicyanoheptafulvene and 6,6-dimethylfulvene. With a dataset size of approximately</div><div>31,000 M062X/def2-SVP quantum mechanical calculations, the computational cost of exploring the reactive potential energy surface was reduced by an order of magnitude. Thousands of virtually costless picosecond-long reactive trajectories suggest that post-transition state bifurcation plays a minor role for the reaction in vacuum. Furthermore, a transfer-learning strategy effectively upgraded the potential energy surface to higher</div><div>levels of theory ((SMD-)M06-2X/def2-TZVPD in vacuum and three other solvents, as well as the more accurate DLPNO-DSD-PBEP86 D3BJ/def2-TZVPD) using about 10% additional calculations for each surface. Since the larger basis set and the dynamic correlation capture intramolecular non-covalent interactions more accurately, they uncover longer lifetimes for the charge-separated intermediate on the more accurate potential energy surfaces. The character of the intermediate switches from entropic to thermodynamic upon including implicit solvation effects, with lifetimes increasing with solvent polarity. Analysis of 2,000 reactive trajectories on the chloroform PES shows a qualitative agreement with the experimentally-reported periselectivity for this reaction. This overall approach is broadly applicable and opens a door to the study of dynamical effects in larger, previously-intractable reactive systems.</div>

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