van derWaals effects on grazing-incidence fast-atom diffraction for H on LiF(001)

J. E. MIRAGLIA; M.S. GRAVIELLE; G. A. BOCAN

PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS

AMER PHYSICAL SOC

Lugar: New York; Año: 2016 vol. 94 p. 22711 - 22721

1050-2947

We theoretically address grazing incidence fast atom diffraction (GIFAD) for H atoms impinging on a LiF(001) surface. Our model combines a description of the H-LiF(001) interaction obtained from density functional theory calculations with a semiquantum treatment of the dynamics. We analyze simulated diffraction patterns in terms of the incidence channel, the impact energy associated with the motion normal to the surface, and the relevance of van der Waals (vdW) interactions. We then contrast our simulations with experimental patterns for different incidence conditions. Our most important finding is that for normal energies lower than 0.5 eV and incidence along the 100 channel, the inclusion of vdW interactions in our potential energy surface yields a greatly improved accord between simulations and experiments. This agreement strongly suggests a non-negligible role of vdW interactions in H-on-LiF(001) GIFAD in the low-to-intermediate normal energy regime.