Sticking of Molecular Hydrogen on a Cold Copper(100) Surface

Using nozzle beams of n-H sub 2 , p-H sub 2 , n-D sub 2 , and o-D sub 2 gases, with incident energies and angles in the ranges 20-75 meV and 30-70 deg , the initial sticking probability, S sub 0 , on a cold ( approx 15K) Cu(100) surface was measured. S sub 0 comprises a smooth background and a series of peaks with max. occurring when the incident energy equals a rotational excitation energy. It is argued that background and structure arise primarily from parallel-momentum--nonconserving phonon processes during the initial collision. 15 ref.--AA