Abstract
General expressions for inductive and dispersive dipolar contributions to the van der Waals interaction between a molecule and a metallic or dielectric nanowire are given. The nonlocal response of the metal is modeled by a standard hydrodynamic dielectric function, which provides exact and analytical expressions for the reflection factors. Numerical calculations are carried out for a HF molecule located at a mean distance from an aluminum wire. A nonpolar molecule (N-2) is then considered in order to avoid any chemisorption effect. The anisotropy of the dispersive van der Waals potential is responsible for rotational transitions of molecules passing in the vicinity of the wire, giving rise to a rotational alignment.