Penetration depth of energetic F atoms from F2 dissociation in layered rare gas samples

Abstract

Penetration depths of atoms with kinetic energy provided by photodissociation of parent molecules in the top layer of a multilayer sample are determined from the probability to cross a spacer layer of thickness d and to arrive at the interface to a substrate. Top layer growth up to a final thickness s corresponds to a continuous increase of the effective spacer layer thickness. Modeling of growth and comparison with sample-to-sample variation of d allows us to determine separately and in a consistent way the precursors’ dissociation cross section q⋅σ and the mean penetration depth d0 of the fragments together with elimination of contaminated samples. For F atoms with 4.3 eV kinetic energy from F2 dissociation values of q⋅σ=3×10−17 cm2 and d0=2.1 nm (8 to 9 monolayers) are derived for Ar spacers. A strong increase of d0 in the case of unintentional multistep excitation of F fragments is demonstrated.

Trapping and thermal migration of the first- and second-row atoms in Ar, Kr and Xe crystals

“…40,42,118,119 As confirmed by the MD simulations 120 and comparative measurements with the polycrystalline films and free-standing crystals, 119 photomobility occurs in the domains of the perfect crystalline structure on the time scale much less than the matrix relaxation time. Special sandwich experiments that allow one to control the penetration depth of the photolytic products 121,122 supported this interpretation. Measurements in Kr and Kr doped by Ar also showed suppressed geminate recombination but revealed other photolytic mechanisms that limit the photomobility, including the charge separation.…”