ROTATIONAL-EXCITATION AND VIBRATIONAL-RELAXATION OF H-2 (UPSILON=1,J=0) SCATTERED FROM CU(111)

We have observed efficient translational to rotational energy transfer for H-2 (nu = 1,J = 2 <-- 0) scattered from Cu(111), the cross sectio n increasing rapidly from near threshold to reach a maximum at a trans lational energy of 140 meV. Above this energy a change in the behavior of the H-2 (nu = 1,J = 2 <-- 0) cross section was seen, coinciding wi th the abrupt onset of H-2 (nu = 1,J) removal by coupling of translati onal and vibrational coordinates. Vibrational relaxation competes with rotational excitation, both processes occurring preferentially at the same impact sites and geometry.