Interaction potentials of Yarkony (1992), matched to new dispersion potentials, are used in calculations by quantal and semiclassical methods of scattering and diffusion cross sections for elastic collisions between hydrogen and deuterium atoms and oxygen atoms, at energies up to 5 eV. Discrepancies among the published values and with the new results are resolved. The coefficients that describe mutual diffusion between hydrogen and oxygen and between deuterium and oxygen at temperatures up to 5000 K are calculated.