Elastic and rotationally inelastic diffraction of D2 molecules from the LiF(001) surface -: art. no. 205430

More than 49 kinematically allowed elastic and rotationally inelastic diffraction peaks of D-2 molecules scattered from a 297 K single crystal LiF(001) surface have been detected in a high resolution scattering experiment for an incident beam energy of 85.3 meV (k(i)=12.8 A(-1)) along the < 100 > and < 110 > azimuthal axes. This comprehensive data set has been collected with a new apparatus, described in some detail, with which high resolution (0.2 degrees) angular distributions can be measured for a wide range of final angles for all incident angles between 0 degrees and 90 degrees. The relative rotational j=0 -> 2 and 1 -> 3 transition probabilities for the specular peak approach 300%, but for rotational transitions associated with a first order diffraction peak the probabilities are typically less than 50% except for grazing incident angles, where a large resonant induced increase is observed. These results provide new evidence for a strong coupling of the rotational transitions to diffraction.