Orientational effects on the molecular diffraction dynamics of H2 scattered from Cu(0 0 1)

We investigate the effects of the correlation between the molecular diffraction and rotational excitation on the dynamics of H2 scattering from Cu(0 0 1) by performing quantum dynamics calculations including all six degrees-of-freedom of H2. We calculate the mj-resolved rotationally inelastic (j=0→2) diffraction (RID) probabilities of H2 (in the vibrational ground state ν=0), scattered from Cu(0 0 1), as a function of the incident energy (j and mj are the corresponding rotational state and the azimuthal state of H2, respectively). Our calculation results show that, apart from some oscillatory structures, the mj-resolved RID probabilities totally increase with increasing incident energies for (j=0→2, mj=0→0), and decrease with increasing incident energies for (j=0→2, |mj|=0→2). Furthermore, our results for the mj-averaged RID probabilities initially increase then decrease with increasing incident energies, which qualitatively agree with recent experimental RID peak results for D2/Cu(0 0 1). Based on our calculation results, we discuss the difference in the RID probabilities between an activated and a non-activated system.