Hydrogen Covered W(110) Surface: A Hydrogen Liquid with a Propensity for One-Dimensional Order

Abstract
The vibrational modes of hydrogen in the saturated W(110)-(1 × 1) phase are indicative of the hydrogen atoms being in a state of a two-dimensional liquid. We propose that the phonon anomalies observed for this phase arise from the propensity of the hydrogen liquid to order in one dimension.