DOES THE ROTATIONAL STATE OF A MOLECULE INFLUENCE TRAPPING IN A PRECURSOR - AN INVESTIGATION OF N-2 W(100), CO/FESI(100) AND O-2/NI(111)/

We have used seeded nozzle beams to obtain molecules of identical tran slational energy but quite different rotational energy to investigate the adsorption dynamics for precursor adsorption in the systems N-2/W( 100), CO/FeSi(100) and O-2/Ni(111). The result of the investigation is unambiguous: there is no discernible influence of the rotational stat e on the sticking coefficient. This is true for an intrinsic as well a s for an extrinsic precursor. This leads to the conclusion that rotati onal energy does not have to be accommodated immediately upon the firs t impact to facilitate trapping. Apparently the molecule can rotate mo re or less freely and the rotational energy can be accommodated subseq uently to trapping. (C) 1997 Elsevier Science B.V.