Acceleration vs Accuracy: Influence of Basis Set Quality on the Mechanism and Dynamics Predicted by Ab Initio Molecular Dynamics

17 September 2019, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Ab initio molecular dynamics (AIMD) is an indispensable tool for understanding the mechanistic details of externally-energy mediated chemical reactions. In this work, we show that the predicted thermodynamic and catalytic properties of certain reactions using AIMD simulations critically depend on the quality of the employed basis set. To this end, we have examined the reactants and products of the water-gas shift reaction (viz., CO, CO2, H2, and H2O) and studied their interaction with the ZnO(101̄0) surface using density functional theory (DFT) and Born Oppenheimer Molecular Dynamics (BOMD) simulations. By merely increasing the quality of the basis, from double zeta (commonly used in most calculations of these systems) to triple zeta, we surprisingly find that the reaction outcome of an H2O molecule colliding with a ZnO surface pre-covered with carbon monoxide gives qualitatively different results. These surprising results are shown to be robust with similar trends that are also obtained with other software packages. Furthermore, we show that the calculated adsorption energies can vary by as much as 380 meV (which is an order of magnitude larger than room temperature) by simply changing the basis set. Using electron density difference maps, we present mechanistic insight into the origin of these changes. Finally, we propose a simple diagnostic test that uses a single-point binding energy calculation to estimate the impact of basis-set quality, which can be used before carrying out a computationally-expensive BOMD simulation.


ab initio molecular dynamics
Born-Oppenheimer molecular dynamics
basis set dependence
water-gas shift reaction
computational chemistry
density functional theory
zinc oxide
chemical reactions
adsorption energy surface
adsorption energy trends

Supplementary materials

Revised Supporting Information for Basis set effect ZnO CO paper


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.