Rotational corrugation in associative desorption of D 2 from Cu(111)

Abstract
We report rotationally state-resolved measurements of the average steric orientation of D2 molecules desorbing from a Cu(111) surface. The desorbing flux of D2 molecules is probed by laser-induced fluorescence with linearly polarized tunable vacuum ultraviolet radiation in the B1Σu+(v',J',M') ← X1Σg+(v'',J'',M''). Molecules desorbing in the vibrational ground state show for all rotational states measured (J'' = 1 − 8) a quadrupole alignment factor, A(2)0, compatible with a spatially isotropic distribution. A strong azimuthal, polar, and lateral corrugation of the dissociative interaction potential can cause this behavior.