The ab initio interatomic distance dependent collision induced dipole moment, polarizability and the vector b(1)(R) and an irreducible 3rd rank tensor b(3)(R) components of the first hyperpolarizability tensor b of He-Ar pair are obtained. The hyperpolarizability data are applied in order to calculate the collision induced He-Ar hyper-Rayleigh spectra both quantum-mechanically and semiclassically for the frequency shifts up to 1200 cm(-1). Computations were carried out for two temperature values - T = 295 K and T = 95 K. Spectral features of both vector and the irreducible 3rd rank tensor parts of CIHR spectra are analyzed. The frequency dependent behavior of the HR depolarization ratio is discussed. (c) 2006 Elsevier B.V. All rights reserved.