Quasi-classical MD study of methane dissociation on the spontaneously missing-row reconstructed Ir(110) surface.

IVÁN F. PELUDHERO; H. FABIO BUSNENGO

San Luis

Encuentro; VIII Encuentro de Física y Química de Superficies; 2018

It is well knownthat the (110) surfaces of late 5d transition-metals [e.g. Ir(110)and Pt(110)] undergo spontaneous missing-row reconstructions 1,2.These processes entail deep changes in the structure of the "ideal"flat unreconstructed surfaces since they alter significantly thecoordination of the exposed metal atoms. In this work we investigatethe reactivity of one of these surfaces, Ir(110), taking thedissociative adsorption of methane as a probe. In the case ofIr(110), several models involving different numbers of missing rowsper unit area have been proposed to rationalize experimental data. Inorder to elucidate possible pathways and mechanisms for methanedissociation, we have used a combination of Density Functional Theory(DFT) calculations and Quasi-Classical trajectory (QCT) calculations.First, we have computed the energy of the transition states for thefirst C-H bond breaking process of methane on the modeled surfaces.Then, we have developed a reactive force field (based on the DFTdata) which was used in the QCT calculations. We investigate themethane dissociation mechanism as a function of the initial kineticenergy of the molecules and surface temperature and the role playedby the molecule-surface Van der Waals interactions.1.Shulz, J. J. , Sturman M. and Koch R. ?Illuminating structuraltransformations of Ir(110): A high-temperature scanning tunnelingmicroscopy study?, Phys. Rev. B. Vol.62, No. 23, 15402-15405, 2000.2.Vlieg, E. , Robinson, I. K. , Kern, K. ?Relaxations in themissing-row structure of the (1×2) reconstructed surfaces of Au(110)and Pt(110)? Surf. Sci., Vol. 233, Issue 3, 248-254, 1990.p { margin-bottom: 0.1in; line-height: 115%; }