Observation of a Change in the Surface Electronic Structure of Pt(100) Induced by Reconstruction

We investigated the clean surface fo a Pt(100) single crystal in its stable (5 ×{} 20) and metastable (1 ×{} 1) configurations by ultraviolet photoelectron spectroscopy, Auger electron spectroscopy, and low-energy electron diffraction. The photoelectron spectrum of the (1 ×{} 1) surface for hν=11.6-40.8 eV is characterized by a narrow peak 0.25 eV below the Fermi level; it is suggested that this peak is due to a maximum in the surface density of states associated with an electronic surface resonance or surface state on the (1 ×{} 1) surface.