  Supramolecular assemblies of lander molecules (C$_{90}$H$_{98}$) on Cu(100)
are investigated with low-temperature scanning tunneling microscopy. The
energetically most favourable conformation of the adsorbed molecule is found to
exist in two mirror symmetric enantiomers or conformers. At low coverage, the
molecules align in enantiomerically pure chains along the chiral directions
$[01\bar{2}],[02\bar{1}],[012]$ and $[021]$. The arrangement is proposed to be
mainly governed by intermolecular van-der-Waals interaction. At higher
coverages, the molecular chains arrange into chiral domains, for which a
structural model is presented.
