## How to Calculate Surface Adsorption Energy for Aluminum

Figure 1. Put one adatom on (111) surface of an fcc Al system along the Z direction. The transverse directions are: X: [-1 -1 2] the longer one; and the Y: [1 -1 0], shorter one.

One adatom is placed on top of the created surface at the next atomic layer distance. There could be different positions of the adatom on top of the surface, such as bridge-site, four-fold site, etc. The entire structure is then relaxed to determine the adsorption energy. It may be found that depending on the adatom site, the adsorption energy will be different for various adsorped sites. The height of the relaxed adatom is also measured from the top surface layer.

#### KPOINTS

```MK11x11x2	#header file
0
Monkhorst	#Style of Kpoints
3  5  1	#Numbers
0  0  0
```

#### POSCAR file for (111) surface having 10 Angstroms in a vacuum containing 104 atoms

```Al_FCC
1.00000000
7.3485      0.00000000      0.00000000
0.00000000   4.24264        0.00000000
0.00000000   0.00000000     30.7846000
CARTESIAN
0            2.1213203                    0
1.8371173            3.1819805                    0
1.8371173            1.0606602                    0
0.61237244            3.1819805            1.7320508
0                    0                    0
0.61237244            1.0606602            1.7320508
3.6742346                    0                    0
3.6742346            2.1213203                    0
2.4494897            2.1213203            1.7320508
2.4494897                    0            1.7320508
5.5113519            3.1819805                    0
5.5113519            1.0606602                    0
4.286607            3.1819805            1.7320508
4.286607            1.0606602            1.7320508
7.3484692            2.1213203                    0
7.3484692                    0                    0
6.1237244                    0            1.7320508
6.1237244            2.1213203            1.7320508
3.0618622            3.1819805            3.4641016
1.2247449                    0            3.4641016
3.0618622            1.0606602            3.4641016
1.2247449            2.1213203            3.4641016
0            2.1213203              5.19615
1.8371173            3.1819805              5.19615
1.8371173            1.0606602              5.19615
0                    0              5.19615
3.6742346                    0              5.19615
3.6742346            2.1213203              5.19615
4.8989795            2.1213203            3.4641016
6.7360968            3.1819805            3.4641016
6.7360968            1.0606602            3.4641016
4.8989795                    0            3.4641016
5.5113519            3.1819805              5.19615
5.5113519            1.0606602              5.19615
7.3484692            2.1213203              5.19615
7.3484692                    0              5.19615
0.61237244            3.1819805            6.9282008
0.61237244            1.0606602            6.9282008
2.4494897            2.1213203            6.9282008
3.0618622            3.1819805            8.6602516
2.4494897                    0            6.9282008
1.2247449                    0            8.6602516
3.0618622            1.0606602            8.6602516
1.2247449            2.1213203            8.6602516
4.286607            3.1819805            6.9282008
4.286607            1.0606602            6.9282008
6.1237244                    0            6.9282008
6.1237244            2.1213203            6.9282008
4.8989795            2.1213203            8.6602516
6.7360968            3.1819805            8.6602516
6.7360968            1.0606602            8.6602516
4.8989795                    0            8.6602516
0            2.1213203              10.3923
1.8371173            3.1819805              10.3923
1.8371173            1.0606602              10.3923
0.61237244            3.1819805            12.124351
0                    0              10.3923
0.61237244            1.0606602            12.124351
3.6742346                    0              10.3923
3.6742346            2.1213203              10.3923
2.4494897            2.1213203            12.124351
2.4494897                    0            12.124351
5.5113519            3.1819805              10.3923
5.5113519            1.0606602              10.3923
4.286607            3.1819805            12.124351
4.286607            1.0606602            12.124351
7.3484692            2.1213203              10.3923
7.3484692                    0              10.3923
6.1237244                    0            12.124351
6.1237244            2.1213203            12.124351
3.0618622            3.1819805            13.856402
1.2247449                    0            13.856402
3.0618622            1.0606602            13.856402
1.2247449            2.1213203            13.856402
0            2.1213203             15.58845
1.8371173            3.1819805             15.58845
1.8371173            1.0606602             15.58845
0                    0             15.58845
3.6742346                    0             15.58845
3.6742346            2.1213203             15.58845
4.8989795            2.1213203            13.856402
6.7360968            3.1819805            13.856402
6.7360968            1.0606602            13.856402
4.8989795                    0            13.856402
5.5113519            3.1819805             15.58845
5.5113519            1.0606602             15.58845
7.3484692            2.1213203             15.58845
7.3484692                    0             15.58845
0.61237244            3.1819805            17.320501
0.61237244            1.0606602            17.320501
2.4494897            2.1213203            17.320501
3.0618622            3.1819805            19.052552
2.4494897                    0            17.320501
1.2247449                    0            19.052552
3.0618622            1.0606602            19.052552
1.2247449            2.1213203            19.052552
4.286607            3.1819805            17.320501
4.286607            1.0606602            17.320501
6.1237244                    0            17.320501
6.1237244            2.1213203            17.320501
4.8989795            2.1213203            19.052552
6.7360968            3.1819805            19.052552       Add the extra adatom somewhere here, such that the Z coordinate of adatom is around 21.
6.7360968            1.0606602            19.052552
4.8989795                    0            19.052552
```