We report interaction dipole moment and (hyper)polarizability calculations for the NeAr diatom, Our values are extracted from finite-field Moller-Plesset, coupled cluster and density functional theory calculations, At an internuclear separation of 6.5a(0), very near the equilibrium of this system, CCSD(T) calculations with a [7s5p4d1f/8s6p5df3] basis set yield the following interaction properties: dipole moment, mu(int) = 0.0022ea(0), mean and anisotropy of the dipole polarizability, (α) over bar (int) = -0.02 and Deltaalpha(int) = 0.59e(2)a(0)(2)E(h)(-1), mean and anisotropy of the first dipole hyperpolarizability, (β) over bar (int) = 2.0 and Deltabeta(int) = 0.1e(3)a(0)(3)E(h)(-2). The B3LYP method provides a reasonable description of the interaction properties of NeAr. (C) 2002 Elsevier Science B.V. All rights reserved.