DFT Comparison of Exact and Approximate Free Energy Calculations for Polyatomic Adsorbates

Master's Thesis


The objective of this work is to compare the various adsorbate free energy approximations by comparing them against a full PES sampling method. Furthermore, we show the impact of free energy model choice on equilibrium predictions of a catalytic reaction model involving polyatomic adsorbates. Focus is placed on comparing the harmonic oscillator and free translator (HO,FT) free energy approximations. The procedure for performing DFT calculations and computing free energies will be given initially. Next, the formulation of the equations of an equilibrium model will be derived and we will explain possible limitations of the model due to the assumptions used. Finally, we will quantify the diļ¬€erences in adsorbate free energy approximations by means of direct comparison and by looking at the sensitivity of model results to free energy calculation method.


Attribute NameValues
Author Gray Laughlin
Contributor William F. Schneider, Research Director
Degree Level Master's Thesis
Degree Discipline Chemical and Biomolecular Engineering
Degree Name MSChE
Defense Date
  • 2018-07-02

Submission Date 2018-07-09
  • English

Record Visibility Public
Content License
Departments and Units


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