The techniques of translational spectroscopy and glancing-incidence molecular ion beam–surface scattering have been combined to study reactive collisions of molecules with surfaces. A clear correlation between the results and known adsorption and reaction behaviour at thermal energies has been established. The similarity between the collision and molecular vibration times permits the identification and investigation of reaction intermediates which may not be detectable by conventional spectroscopies. The technique, which can in principle also measure the molecular orientation to the surface during scattering, should provide valuable insights into the dynamics of adsorption and reaction, both molecular and dissociative, on surfaces. Explicit results for the interaction of N2 with Ni(110) and (111), O2 with Ag(111) and Ni(110), and CO and CO2 with Ni(110) surfaces are presented.