Influence of incidence angle on hydrogen and deuterium atoms interaction with a cesiated surface

Molecular Dynamics simulations have been conducted to highlight the influence of incidence angle on the H- (D-) production when a flux of H(D) atoms impacts on a cesiated surface. A new interaction potential for H atoms impinging the surface with incidence angle (?) of 45° was determined via first principle electronic structure calculations including both the interaction with Cs and Mo atoms in the surface. The incident angle effect on the scattering probability appears most evidently for medium-high energies, being negligible for the low collisional energy regime. In particular, for ?= =45° and for medium-high energies the production of negative ions decreases in the case of H while increases for incident D atoms with respect to the normal incidence. The mass effect is also evident in the final angular distributions of reflected negative ions. The mechanism underlying the interaction and in particular the role of surface phonons is pointed out.