State-of-the-Art Reviews on Energetic Ion-Atom and Ion-Molecule Collisions

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

World Scientific Publishing

Lugar: Singapur; Año: 2019 p. 27

978-981-121-160-7

We present precise representations of the atom-LiF(001) interaction for both multielectronic and hydrogen atoms. For the former we introduce a pairwise additive (PA) potential model that includes an improved description of the electron density associated with the different lattice sites, as well as non-local electron density contributions. We apply this PA model to evaluate the interaction potential between closed-shell - He, Ne, Ar, and Kr - and open-shell- N, S, and Cl - atoms and the LiF surface. In turn, for H projectiles we build a high-precision interaction potential from density functional theory calculations, which properly takes into account the reactivity of the H-LiF(001) system, including the contribution of van der Waals (vdW) forces.The performance of the proposed potentials is assessed by contrasting angular projectile distributions produced by fast grazing incidence with available experimental data. For multielectronic projectiles, the angular positions of rainbow and supernumerary rainbow maxima derived within the PA potential are ingood agreement with the experiments, confirming the validity of the potential model in a wide normal energy range, from 0.2 to 80 eV. In all the cases vdW contributions are estimated as negligible. In contrast, for H atoms the comparison of our simulations with experimental grazing-incidence fast atom diffraction patterns strongly suggests a non-negligible role of vdW interactions in the low normal energy regime when incidence is along the channel.