کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5426140 | 1395878 | 2007 | 9 صفحه PDF | دانلود رایگان |
Many theoretical studies already dealt with the interaction of one H2 molecule with a metallic surface, but so far none aimed at the description of the interaction of additional layers of molecules, which is the goal of the present work. A model system consisting of a cluster of 13 Cu atoms and two/three H2 molecules has been used to calculate with highly correlated wavefunctions the interaction of successive layers of H2 with a surface of copper already covered by chemisorbed, dissociated H2 molecules. A second H2 molecule, approaching the Cu surface with different orientations, on top of a first one, is not dissociated and its physisorption interaction with the surface is calculated to be in the range 600-1000Â cmâ1, approximately twice that of the first H2 molecule. The physisorption interaction of H2 molecules forming a third layer is estimated to be in the range of 60-100Â cmâ1, which is much smaller than the interaction of the second layer with the surface but still larger than the H2/H2 interaction between a pair of isolated molecules. It is shown that this effect mainly results from the interactions with the ions Hâ and Cu+ formed on the surface.
Journal: Surface Science - Volume 601, Issue 2, 15 January 2007, Pages 320-328