Pseudofunction method: Application to a monolayer of CO and to the Si(111) surface.

The newly developed pseudofunction method has been developed to provide ab initio energy bands and binding-energy curves for molecules, surfaces, and bulk. The effectiveness of this approach is demonstrated by computing the electronic properties of a CO molecule in a monolayer configuration. We find the CO bond length, dipole moment derivative, and the vibrational frequency are close to that of a free CO molecule. We have further demonstrated this new method by computing the surface relaxation of a Si(111)(1\ifmmode\times\else\texttimes\fi{}1) four-layer film with one surface saturated by H. The unsaturated surface relaxes inwards by 0.086 A\r{} with a vibrational excitation of 0.038 eV, nearly identical to generalized-valence-bond cluster calculations.