Scattering of particles from surfaces is a useful tool for probing surfaces. Detailed experimental results for the scattering of Ar from a LiF(001) surface are available for more than 10 years [3,4]. The angular distribution which is associated with the scattering along the [100] surface direction possesses a double peak asymmetric structure. As the incident energy of the Ar atom is decreased the peak-to-peak distance and the asymmetry of the angular distribution are increased. On the other hand, the scattering process along the [110] surface direction yields a uni-modal structure, where as the incident energy of the Ar atom is decreased the angular distribution is shifted towards lower scattering angles.

In the current presentation we suggest a realistic approach to model the aforementioned scattering process. A precise fit to the 3 dimensional ab-initio potential of the Ar-LiF(001) system is suggested and the classical dynamics is worked out numerically. A quantitative agreement with experimental results and a better un derstanding of the scattering process are achieved. Several lessons come out of this study: (1) The functional form of the realistic potential is unravelled. (2) The corrugation of the potential along the [100] surface direction is much stronger than above the [110] surface direction which affects largely the measurements of bi- and uni-modal structures of the angular distributions. (3) We show the effect of the second horizontal dimension (y) on the in-plane (x, z) angular distribution. (4) The scattering along the [110] surface direction takes place especially above the lines which connect the Li or F atoms, whereas the scattering along the [100] surface direction is 3 dimensional where the Ar atom travels temporarily in the y direction while it is in the vicinity of the surface.

[1] Asaf Azuri and Eli Pollak, J. Chem. Phys. 139, 044707 (2013).
[2] Asaf Azuri and Eli Pollak, J. Chem. Phys. 143, 014705 (2015).
[3] T. Kondo, H. S. Kato, T. Yamada, S. Yamamoto, and M. Kawai, J. Chem. Phys. 122, 244713 (2005).
[4] T. Kondo, H. S. Kato, T. Yamada, S. Yamamoto, and M. Kawai, Eur. Phys. J. D. 38, 129 (2006).