Personal tools
You are here: Home Highlights Wanda2012 Ab Initio Study of CO2 Interacting with Water Molecules
Log in


Forgot your password?
 

Ab Initio Study of CO2 Interacting with Water Molecules

— filed under:

Bridging Static and Dynamical Descriptions of Chemical Reactions: An ab Initio Study of CO2 Interacting with Water Molecules

Cover JCTC

 

Grégoire A. Gallet, Fabio Pietrucci, and Wanda Andreoni

J. Chem. Theory Comput., 2012, 8 (11), pp 4029–4039 

 

Abstract

 

Extracting reliable thermochemical parameters from molecular dynamics simulations of chemical reactions, although based on ab initio methods, is generally hampered by difficulties in reproducing the results and controlling the statistical errors. This is a serious drawback with respect to the quantum-chemical description based on potential energy surfaces. This work is an attempt to fill this gap. We apply molecular dynamics, based on density functional theory (DFT) and empowered by path metadynamics (MTD), to simulate the reaction of CO2 with (one, two, and three) water molecules in the gas phase. This study relies on a strategy that ensures a precise control of the accuracy of the reaction coordinates and of the reconstructed free-energy surface on this space, namely, on (i) fully reversible MTD simulations, (ii) a committor probability analysis for the diagnosis of the collective variables, and (iii) a cluster analysis for the characterization of the reconstructed free-energy surfaces. This robust procedure permits a meaningful comparison with more traditional calculations of the potential energy surfaces that we also perform within the same DFT computational scheme. This comparison shows in particular that the reactants and products of systems with only three water molecules can no longer be understood in terms of one structure but must be described as statistical configuration ensembles. Calculations carried out with different prescriptions for the exchange-correlation functionals also allow us to establish their quantitative effect on the activation barriers for the formation and the dissociation of carbonic acid. Their decrease induced by the addition of one water molecule (catalytic effect) is found to be largely independent of the specific functional.

Document Actions
« May 2017 »
May
MoTuWeThFrSaSu
1234567
891011121314
15161718192021
22232425262728
293031