Rotational Excitation and Vibrational Relaxation of H2 (υ=1, J=0) Scattered from Cu(111)

We have observed efficient translational to rotational energy transfer for H2 (υ=1, J=2 left-arrow 0) scattered from Cu(111), the cross section increasing rapidly from near threshold to reach a maximum at a translational energy of 140meV. Above this energy a change in the behavior of the H2 (υ=1, J=2 left-arrow 0) cross section was seen, coinciding with the abrupt onset of H2 (υ=1, J) removal by coupling of translational and vibrational coordinates. Vibrational relaxation competes with rotational excitation, both processes occurring preferentially at the same impact sites and geometry. copyright 1997 The American Physical Society