The frequency-dependent linear response approach for the hierarchy of coupled cluster methods CCS/CC2/CCSD/CC3 has been used to evaluate geometric derivatives of polarizabilities and Q-branch Raman scattering cross-sections of five diatomics: N-2, CO, HF, HCI and Cl-2. The triple excitation corrections are substantial for N-2 and CO. where they exceed 10%, and negligible for HF and HCl. The results at the CCSD and CC3 levels with correlation-consistent basis sets have been used to obtain best estimates for the Raman scattering cross-sections. The agreement between the estimated values and experiment is satisfactory, considering the approximations inherent in the harmonic approach and Placzek's polarizability theory. (C) 2002 Published by Elsevier Science B.V.