Ab initiostudy of diamond C(100) surfaces

We use ab initio local-density-approximation methods to study the electronic and geometrical structure of the various C (100) surfaces. The calculated densities of states suggest that the surface states observed for the (21) surface are attributable only to the clean C (100) (21), not the C (100) (21): H. The hypothetical C (100) (11): 2H is found to be energetically unstable. The C (100) (31): 1. 33H is found to be favored over the C (100) (21): H. H desorption energies are calculated.