Vibrational and rotational coupling effects in the direct scattering of H-2 from Cu(111)

We investigate how the coupling between molecular vibration and rotation af fects the direct scattering of H-2 from Cu(111) by performing coupled chann el calculations, Our calculation results show that the rotational excitatio n probability of H-2 scattered (vibrationally elastic) in the first vibrati onally excited state (nu = 1) increases more rapidly than that of H-2 scatt ered (vibrationally elastic) in the vibrational ground state (nu = 0) with increasing translational energy in the low translational energy region. Fur thermore, the calculation results for the ratio of the probability of H-2 s cattered in nu = 1 and rotational state J = 2 to the probability of H-2 sca ttered in nu = 1 and J = 0 as a function of translational energy qualitativ ely reproduce the experimental results in the low translational energy regi on. (C) 1999 Elsevier Science B.V. All rights reserved.