Molecule-substrate vibration of CO on Ni(100) studied by infrared-emission spectroscopy

A novel infrared-emission technique has been used to make the first measurement of the linewidth of a molecule-substrate vibrational mode on a well characterized single-crystal surface. At saturation coverage, the observed linewidth of the C-Ni mode of CO on Ni(100) is 15 cm-1. This result is in agreement with predictions for broadening due to deexcitation by two-phonon emission. © 1984 The American Physical Society.