Molecular effects in H2 scattering from metal surfaces at grazing incidence

Collisions of fast atoms with surfaces at grazing incidence have been recently proposed as a promising new tool to determine surface parameters with unprecedented accuracy. Here we show, by means of classical dynamics calculations performed with first-principles six-dimensional potential energy surfaces for H2/NiAl(110) and H2/Pd(111) that, under grazing incidence conditions, fast light molecular projectiles are also useful to determine sticking probabilities at thermal energies, from the threshold up to the saturation limit. Thus they are the ideal complement to traditional experiments at thermal energies to determine sticking curves up to the saturation limit.