The vibrational line shape of CO on Cu(100)

Abstract

Publisher Summary This chapter discusses the vibrational line shape of CO on Cu(100). The shape of the infrared absorption peak of the internal stretch vibrational mode of CO adsorbed on Cu(100) has been studied. There is no temperature dependence of the width in the 20-130 K range, indicating that thermally excited, low frequency modes are not involved in the peak broadening process. A peak shape analysis indicates that the broadening is homogeneous for the ordered c(2x2) structure and hence that the width is a good measure of the vibrational lifetime. The small asymmetry that for the ordered structure and that becomes more pronounced for an incomplete layer is caused by inhomogeneities in the adsorbate layer. However, there are recent line shape theories, which predict an asymmetric peak for electron-hole pair damped vibrational excitations.