Rotational population and alignment in the scattering of N 2 off Ag(111): Multidimensionality and Energy Loss effects.

G.A. BOCAN; J.I. JUARISTI; M. ALDUCIN; R. DÍEZ MUIÑO

Rio de Janeiro

Conferencia; XVII International Conference on Solid Films and Surfaces; 2014

ICSFS

Rotationally inelastic scattering provides valuable information on gas-surface interaction [1] particularly through the sensitivity of alignment to the anisotropy of the potential energy surface [2]. In this work we perform a theoretical characterization of N 2 scattered off Ag(111), focusing on the scattering dynamics, rotational population and alignment. Molecules scattered into higher rotationally excited Jf states are found to be reflected farther away from the surface than lower Jf ones. This non- intuitive result is explained by means of a detailed 6D analysis of the scattering dynamics. Regarding rotational population and alignment we show that, notwithstanding phonon excitations and multidimensionality effects play only a minor role in the former, multidimensionality is central for an accurate description of the alignment, even for an almost flat system such as N 2 /Ag(111). In fact, while calculations within a 2D-(ZCM, θ) model fail to reproduce available experimental results [3], excellent agreement is reached with a full 6D dynamics. G.A.B. acknowledges support from ANPCYT (PICT 2010-1558) and from CONICET (PIP 112 201201 00272 CO). J.I.J, M.A. & R.D.M. acknowledge support from the Basque Departamento de Educación, Universidades e Investigación, the University of the Basque Country UPV/EHU (Grant No. IT-756-13) and the Spanish Ministerio de Ciencia e Innovación (Grant No. FIS2010-19609-C02-02). [1] Dynamics of Gas-Surface Interactions, edited by R. Díez Muiño and H.F. Busnengo (Springer, Heidelberg, 2013) [2] L. Vattuone, L. Savio, F. Pirani, D. Cappelletti, M. Okada, and M. Rocca, Prog. Surf. Sci. 85, 92 (2010) [3] G. O. Sitz, A.C. Kummel, and R.N. Zare, J. Chem. Phys. 89, 2558 (1988)