Phillips et al. 1996
Phillips, T.R., S. Maluendes, and, 1996: Collisional excitation of H2O by H2 molecules. Astrophys. J. Supp. Series, 107, 467-474, doi:10.1086/192372.
Using an accurate theoretical rigid-rotor interaction potential for H2O-H2 and accurate coupled channel molecular scattering calculations, rates have been obtained for excitation of para- and ortho-water out of the lowest, j = 0, 1, and 2, rotational levels owing to collisions with para- and ortho-H2 at kinetic temperatures from 20 K to 140 K. Excitation by para-H2 is not too different from excitation by He atoms, with most rates being within a factor of 1-3 larger, but excitation by ortho-H2 is significantly different, with some rates an order of magnitude larger than rates for excitation by He atoms.