Many Thanks Jens, Meanwhile I've tried adlayer = fcc111('Au', size=(5, 4, 1)) add_adsorbate(slab,adlayer, a ,position='fcc') -------------- next part -------------- An HTML attachment was scrubbed... URL: http://listserv.fysik.dtu.dk/pipermail/gpaw-users/attachments/20111024/db31e6fc/attachment.html