The photolysis of NO dimers, adsorbed on an MgF2 surface, at 248 nm

The dynamics of the photolysis of NO dimers, and subsequent desorption of NO, from a single crystal MgF2 surface have been investigated using resonance-enhanced multi-photon ionisation spectroscopy. The rotational distribution of NO(ν″ = 2) is correlated with its velocity. For a velocity of 1500 m s−1 there is a Gaussian distribution of rotational states, peaking at J = 35.5; lower velocities show progressively colder distributions. It is suggested that these changes are due to collisional deactivation of rotation and translation, but not of vibration, of NO(ν, J) on the surface prior to desorption.