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Ta(110) Surface And Subsurface Core-Level Shifts And 4f7/2 Lineshapes, D. Mark Riffe, G. K. Wertheim
Ta(110) Surface And Subsurface Core-Level Shifts And 4f7/2 Lineshapes, D. Mark Riffe, G. K. Wertheim
All Physics Faculty Publications
High-resolution 4f core-level spectra of the Ta(110) surface region have been obtained at 80 and 300 K with 70- and 100-eV synchrotron radiation. The data show that the subsurface core-level binding-energy shift (compared to deeper-lying atoms) for a close-packed bcc(110) surface can be substantial: 65±15 meV for the first underlayer atoms of Ta(110). The surface core-level shift is 360±12 meV at 80 K and decreases by 13±2 meV at 300 K. Final-state screening in both the bulk and surface layers is well described by a constant singularity index of 0.133±0.012. An enhanced phonon broadening at the surface corresponds to a …
Chemical And Reconstruction Induced Surface Core-Level Shifts: H On Low-Index W Surfaces, D. Mark Riffe, G. K. Wertheim, P. H. Citrin
Chemical And Reconstruction Induced Surface Core-Level Shifts: H On Low-Index W Surfaces, D. Mark Riffe, G. K. Wertheim, P. H. Citrin
All Physics Faculty Publications
The H-induced shift of the surface-atom core-level binding energy in W(110) is shown to arise from two distinct effects, one chemical in nature and the other structural. The structural shift supports a recently proposed (1p×1) reconstruction that turns on at ∼0.5 monolayer coverage. These new findings are used to provide a self-consistent interpretation of previously reported shifts from H-covered W(111) and W(100) surfaces.