Accession Number : ADA258578


Title :   Vibrational Spectroscopic Studies of Adsorbates on Bimetallic Surfaces.


Descriptive Note : Doctoral thesis


Corporate Author : TEXAS A AND M UNIV COLLEGE STATION DEPT OF CHEMISTRY


Personal Author(s) : Kuhn, William K


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a258578.pdf


Report Date : Dec 1992


Pagination or Media Count : 163


Abstract : In this work, well-defined bimetallic surfaces have been studied using carbon monoxide adsorption in conjunction with infrared reflection absorption spectroscopy (IRAS). These studies have indicated that for CO adsorbed on Cu overlayers, the bond between the CO and the Cu adatoms is comprised of both pi-back-donation and polarization interaction components. The sum of the contributions from these effects determines the observed bond strength with the observed CO stretching frequency being determined by the relative contributions of the components. In addition, it was determined that IR spectra of adsorbed CO show a remarkable sensitivity to surface structure. Three-dimensional Cu clusters, well-ordered two dimensional Cu islands and isolated Cu atoms are distinctively characterized by their CO IR peaks. In addition, both disorder-order and order-order transitions are observed for the metal overlayers on the single crystal metal substrates. It was also observed that localized segregation and ordering of mixed Co and S overlayers on a Mo(110) substrate occurs upon annealing.


Descriptors :   *METALS , *SPECTROSCOPY , *SURFACES , *ADSORBATES , ANNEALING , STRUCTURES , SINGLE CRYSTALS , SUBSTRATES , REFLECTION , THREE DIMENSIONAL , SORPTION , TANTALUM , CARBON MONOXIDE , SULFUR , SURFACE CHEMISTRY , TRANSITIONS , NICKEL , COPPER , SPECTRA , RHODIUM , ADATOMS , ADDITION , MONOXIDES , COBALT , CHEMICAL BONDS , SENSITIVITY , CRYSTALS , MOLYBDENUM , THESES , TWO DIMENSIONAL , VIBRATION


Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Properties of Metals and Alloys
      Atomic and Molecular Physics and Spectroscopy


Distribution Statement : APPROVED FOR PUBLIC RELEASE