Addicoat, Matthew A.Lim, Kieran F.Metha, Gregory F.2015-12-012015-12-010021-9606http://hdl.handle.net/1885/16935Calculated energy profiles for the reactions of neutral Nb₂ and Nb₃ metal clusters with CO, D₂, N₂, and O₂ are presented. In each reaction path, both a physisorption energy minimum, where the reactant remains intact, and a chemisorption energy minimum, where the reactant has dissociated, are calculated and linked by saddle points. We calculate branching ratios for the forward (dissociative) and reverse reactions which we compare with the experimental kinetic data. It is found that a combination of average thermal energies and barrier heights leads to wide variation in branching ratios which compares favourably to previously determined experimental reaction rates.This work was supported by an award under the Merit Allocation Scheme on the National Computational Infrastructure (NCI) National Facility at the Australian National University (ANU). Additional computer time was provided by eResearch South Australia (eRSA). M.A.A. acknowledges the JSPS Fellowship program. K.F.L. thanks the University of Canterbury (New Zealand) for a Visiting Erskine Fellowship.http://www.sherpa.ac.uk/romeo/issn/0021-9606..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 1/12/15). Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in The Journal of Chemical Physics and may be found at https://doi.org/10.1063/1.4733287Keywords: Barrier heights; Branching ratio; Chemisorption energy; Density functionals; Energy profile; Experimental kinetics; Metal cluster; Physisorption energy; Reaction paths; Reaction profile; Reverse reactions; Saddle point; Chemisorption; Density functional t2012-07-1610.1063/1.47332872016-02-24