Scanning-tunneling microscopy, near-edge X-ray-absorption fine structure, and density-functional theory studies of N₂O orientation on Pd(110)

The orientation of adsorbed N₂O on Pd(110) was studied by scanning tunneling microscopy, near-edge X-ray absorption fine structure (NEXAFS), and density functional theory. Below 14 K, N₂O(a) forms clusters extending along the [11̄0] direction as well as monomers oriented along the [001] direction. In the clusters, N₂O is tilted with the terminal nitrogen bonding to the surface. The clusters are mobile at 14 K and stable at 8 K, whereas the monomers are stable at 14 K. In NEXAFS work at 60 K, remarkable anisotropy was found in the polarization dependence of π resonance, which was consistent with a mixture of the tilted and [001]-oriented forms.