Tunable-diode-laser infrared reflection absorption spectroscopy of carbon monoxide on Pt(111)

Abstract

A tunable-diode-laser infrared spectrometer has been constructed to study submonolayer coverages of adsorbed molecules on metal and metal oxide surfaces. Infrared reflection absorption spectra of the C-O stretch mode for the on-top site of CO adsorbed on a Pt(111) single crystal were obtained in the temperature range 88--300 K. Linewidths of 3 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ were observed at the lower temperatures. The temperature dependence of the center frequency and linewidth is interpreted in terms of relaxation dephasing.