Dynamics of H chemisorbed on Si(100) and W(100) studied by high-resolution infrared spectroscopy.

Spectral line shapes are used to study dynamics of H chemisorbed on two different types of substrates, a semiconductor, Si(100), and a metal, W(100). Dephasing is found to dominate the linewidth of the Si-H stretching mode and lifetime broadening is estimated to be negligible. For the W(100)H system, a strong coupling between the wagging mode and surface electronic states dominates the line shape of the overtone of the wagging mode. This coupling provides an efficient decay channel by the production of electron-hole pairs. These two examples are used to assess the usefulness of high resolution spectral measurements in the study of energy transfer mechanisms between adsorbates and substrates.