van der Waals interaction between an atom and a metallic nanowire

The nonretarded linear-response potential of a metallic cylindrical nanowire in the vicinity at which an atom, assimilated to a fluctuating dipole, is placed is determined using (i) a complete orthogonal basis set over which the potential inside the solid is expanded and (ii) the boundary conditions at the solid surface. Exact analytical expressions of the reflection factors are obtained. The dipole-dipole van der Waals energy is then derived by use of the propagator method. This energy is numerically calculated for an argon atom in the vicinity of an aluminum wire. At short distance a repulsive potential, calculated by summing terms in r(-12) over the solid lattice, is added to the previous one. The collision at thermal energies of Ar atoms with the Al wire is then studied. The potential well makes a rainbow effect appear at angles easily accessible experimentally.