Surface-state--surface-resonance transition on Ta(011)

High-resolution angle-resolved-photoemission results are presented which probe in detail the transition of intrinsic surface bands on clean and hydrogen-covered Ta(011) from pure states to resonances. This is manifested by both a resonant broadening of ∼0.5 eV and a level shift. An unusual avoided crossing between surface and bulk bands is observed in which the surface and bulk characters are interchanged. The resultant hybridization of surface and bulk bands near the crossing has not previously been observed