Reflectometric spectroscopy of adsorbed molecular layers.

A normal-incidence technique is described for obtaining IR absorption spectra of molecular layers adsorbed on a dielectric thin-film surface. In the experiment described, a low-power CO(2) laser beam is scanned across a molecular layer of 2-propanol adsorbed on a ZnSe film. Spectra for 1-5 monolayer coverages are compared with the liquid spectrum of the adsorbate.