Vibrational spectra of atomic adsorbates: Carbon, oxygen, and sulfur on Rh (100)

Abstract

High resolution electron energy loss spectroscopy(EELS), low‐energy electron diffraction(LEED), and Auger electron spectroscopy(AES) were used to study the adsorption of ordered carbon, oxygen, and sulfur overlayers on a Rh (100) single crystal surface at 300 K. Each adsorption system was characterized by a single vibrational frequency; νRh–C=535, νRh–O=403, and νRh–S=313 cm−1. The observed high resolution EELSspectra of all of these species is consistent with the bonding of adsorbed atoms in the highest coordination site on the Rh (100) surface. During the course of these experiments, modes corresponding to rhodium surface phonons (181, 272 cm−1) and to adsorbed carbon monoxide (bridged: 358, ∼1920; linear: 428, ∼2030 cm−1), boron oxides (740, 950, 1405 cm−1), and disulfur (585 cm−1) were identified. High resolution EELS is clearly a powerful tool for studying the latter two species since they have not been detected by other spectroscopic techniques.