Molecular dynamics study of methane dissociation on Ni(111) and Pt(111)

A. LOZANO; X. J. SHEN; W. DONG; H. F. BUSNENGO

Potsdam

Workshop; 2nd International Workshop on Scattering of Atoms and Molecules from Surfaces; 2013

Universität Potsdam

Highly accurate reactive force fields (RFF), based on the Tersoff bond order formalism [1-2], are constructed for CH4 interacting with the Ni(111) and Pt(111) surfaces. The RFFs are fitted to a database based on density-functional-theory (DFT) calculations. The agreement between the built RFF and the DFT results is excellent for the geometry and energy of the transition states (TS) and the vibrational spectrum of the molecule. With these parametrized PES we investigate the dissociative adsorption of CH4 and its deuterated isotopologues through QuasiClassical trajectory (QCT) calculations. The RFFs and the QCT method are validated by the good agreement between theoretical and experimental state-selective probabilities [3-6]. The present calculations also allow us to rationalize the recently measured high C-H bond selectivities [7], induced by excitation of particular stretching modes in deuterated isotopologues and also predict the conditions to achieve similar high selectivity for the the less reactive C-D bonds. [1] Tersoff, Phys. Rev. B 38, 9902 (1988) [2] Xiao et al, J. Chem. Phys. 132, 014704 (2010) [3] Smith et al., Science 304, 992 (2004) [4] Juurlink et al., Phys. Rev. Lett. 94, 208303 (2005) [5] Chen, Huang and Utz, J. Phys. Chem. A 117, 6250 (2013) [6] Chen et al., Rev. Sci. Instrum. 84, 053902 (2013) [7] Chen, Ueta, Bisson and Beck, Faraday Discuss. 157, 285 (2012)