Angle-resolved photoemission study of clean and hydrogen-saturated Mo(110)

We present the development of Fermi-level crossings from the clean to the h ydrogen-saturated (110) surface of molybdenum at room temperature. The well -known adsorbate-induced phonon anomaly is discussed in terms of a quasi-on e-dimensional Fermi-surface nesting and giant Kohn anomaly. Our experiment resolved an existing discrepancy between earlier photoemission data and Fer mi-surface contours calculated within density-functional theory. Moreover, it is found that the Fermi-surface nesting is fully established at hydrogen coverages where the phonon anomaly just barely forms.