Elementary reactive processes of nitrogen and hydrogen on metal surfacesA theoretical study

Résumé

We present a theoretical study of elementary reaction take place at solid surfaces. Calculations based on density functional theory (DFT) were performed to obtain the minimum energy structure of the Fe(111) surface as well as the use of first-principle calculations to describe the interaction of N and N2 with the Fe(111) surface. The most difficult part of this task is to codify into a single function, namely, the potential energy surface (PES), the full energy landscape of the system. Finally, we performed classical trajectory calculations in order to study the dissociative and non-dissociative adsorption mechanisms of N2 on the Fe(111) surface. The final analysis of these calculations allow us to understand the dynamics of the different reaction channels of nitrogen on the most reactive iron face Fe(111).A complementary point of the work is the study of the isotope substitutions of hydrogen in the Eley-Rideal recombination mechanisms on the H(D,T) pre-covered tungsten surfaces W(110) and W(100). The recombination of atoms with other atoms already adsorbed at the surface is another physico-chemical process of great interest. The theoretical description is in this case more involved due to the large surface areas required to properly describe the dynamics. We think that it is relevant to include the study in this thesis in order to give an example of other elementary reactive processes that may occur at metal surfaces.