The rotational excitation of CO by H2

Cross sections and rate coefficients have been calculated for the rotational excitation of CO by ground state ortho- and para-H 2 . The quantum-mechanical-coupled-channels method was used, without significant approximations other than the finite size of the basis sets. For collisions with ortho-H 2 , rotational levels of CO j ⩽20 were included, and j ⩽29 for collisions with para-H 2 . Comparison is made with recent calculations by Mengel et al (2001 Can. J. Phys. at press).