Heterogeneous catalyzed processes are highly significant to the chemical industry. Dissociative chemisorption (DC) of molecules on surfaces is always considered as a step with a high degree of rate... Show moreHeterogeneous catalyzed processes are highly significant to the chemical industry. Dissociative chemisorption (DC) of molecules on surfaces is always considered as a step with a high degree of rate control for heterogeneous catalysis. Our ability to comprehend the different mechanisms underlying DC on metal surfaces could benefit significantly from the availability of an accurate database for the barrier heights of elementary molecule-metal surface reactions. In this work, we used a recent implementation of specific reaction parameter (SRP) to density-functional theory (DFT) (SRP-DFT) to develop potential energy surfaces (PESs) for molecule-surface reactions. The PESs were used for molecular beam simulations and compared with molecular beam experiments. The barrier heights extracted from these PESs are now used for benchmarking. Show less
Metals surfaces form a group of effective catalysts for the reaction of small molecules such as hydrogen (H2). In order to improve the predictive power of theory with respect to the catalytic... Show moreMetals surfaces form a group of effective catalysts for the reaction of small molecules such as hydrogen (H2). In order to improve the predictive power of theory with respect to the catalytic activity of small molecules reacting at metal surfaces, the way in which metal surfaces modify the potential energy of molecules needs to be understood at a fundamental level. Currently density functional theory (DFT) is the only electronic structure method that is accurate enough to achieve chemical accuracy while being cheap enough to make large comparative studies feasible. The work in this thesis is concerned with the creation of highly accurate density functionals that can give a simultaneously good description of the metal surface, the molecule, and the molecule interacting with the metal surface, as well as the description and simulation of supersonic molecular beam experiments and associative desorption experiments needed to validate the obtained results. Show less
Nour Ghassemi, E.; Wijzenbroek, M.; Somers, M.F.; Kroes, G.J. 2017
Using semi-empirical density functional theory and the quasi-classical trajectory (QCT) method, a specific reaction parameter (SRP) density functional is developed for the dissociation of... Show moreUsing semi-empirical density functional theory and the quasi-classical trajectory (QCT) method, a specific reaction parameter (SRP) density functional is developed for the dissociation of dihydrogen on Pt(1 1 1). The validity of the QCT method was established by showing that QCT calculations on reaction of D2 with Pt(1 1 1) closely reproduce quantum dynamics results for reaction of D2 in its rovibrational ground state. With the SRP functional, QCT calculations reproduce experimental data on D2 sticking to Pt(1 1 1) at normal and off-normal incidence with chemical accuracy. The dissociation of dihydrogen on Pt(1 1 1) is non-activated, exhibiting a minimum barrier height of −8 meV. Show less
