Take the above table as reference for the orders of magnitude of surface energies. You can download the commented inputs by downloading from the wiki: exercise_3.2.zip) the necessary files for computing the surface energies of all 3 high symmetry faces of gold. In principle all reconstructed phases should be with a lower surface energy, but this EAM potential fails for some of them. The input files are:

1. 100_bulk.inp for determining the energy per atom in the bulk
2. 100_unr.inp for the bulk termination (100)
3. 100_rec.inp for the hexagonally reconstructed (100)
4. 110_unr.inp for the (110) bulk termination
5. 110_rec.inp for the (2×1) reconstruction
6. 111.inp for the unreconstructed (111).

The compute_surf scripts give an idea how to compute the surface energies. Assignments:

1. Mark surface energies and relaxations of the first 2-3 top layers (use vmd or editor)
2. Try to color the surfaces in vmd in a way that makes the height evident (ask the assistant) and produce snapshots (render)
3. Comment on the (2×1) reconstruction: what do you see?
4. Plot the same, but adding periodic images in vmd: remember pbc set { a b c 90 90 90 }.