A realistic calculation was made of the equilibrium surface structure and vibrational excitations of the hydrogenated Si(001)-(2 x 1) surface. A saturation monohydride coverage was found to produce a (2 x 1) surface of symmetrical dimers. A variety of interesting surface vibrational modes was found; including a band of high-frequency vibrations associated with fivefold rings formed by the surface reconstruction. The relationship between surface structure and surface vibrational modes was further elucidated by comparison with similar vibrational modes found on clean reconstructed Si(001)-(2 x 1). The results for Si-H bond bending and stretching frequencies agreed with experimentally measured values for this surface.

Surface Reconstruction and Lattice Dynamics of Hydrogenated Si(001):2 x 1. D.C.Allan, E.J.Mele: Physical Review B, 1985, 31, 5565-8