AVS 51st International Symposium
    Surface Science Monday Sessions
       Session SS1-MoA

Paper SS1-MoA6
Determination of Adsorption Site for Isocyanides and Aminocarbynes on Pt(111) from Theoretical and Experimental Vibrational Spectra

Monday, November 15, 2004, 3:40 pm, Room 210B

Session: Simulation and Theory of Adsorption
Presenter: E. Herceg, University of Illinois at Chicago
Authors: E. Herceg, University of Illinois at Chicago
B. Chatterjee, University of Illinois at Chicago
M. Trenary, University of Illinois at Chicago
Correspondent: Click to Email
Density funcional theory (DFT) calculations have been used to study the bonding, geometry, and influence of basis set size on the vibrational properties of methyl-isocyanide (CH@sub 3@NC) and aminocarbyne species (CNH@sub 2@ and CNHCH@sub 3@) bonded to different Pt clusters. Calculated spectra were compared with the RAIRS data obtained for the corresponding species adsorbed on the Pt(111) surface. We used Pt, Pt@sub 7@H@sub 6@, Pt@sub 2@, Pt@sub 9@H@sub 14@, and Pt@sub 4@ clusters in order to provide models for adsorption at on-top, two-fold bridge, and three-fold hollow sites. Comparison between experimental and calculated spectra showed that CH@sub 3@NC is bonded to the surface at on-top site for low coverages and at both on-top and bridge sites for high coverages. For aminocarbynes bonded to Pt@sub 2@ and Pt@sub 9@H@sub 14@ (models of the twofold bridge site) calculations successfully reproduce experimental spectra. No significant improvement was achieved by using the Pt@sub 9@H@sub 14@ cluster compared with the Pt@sub 2@ model. On the other hand better agreement between experimental and simulated spectra of CH@sub 3@NC and CNH@sub 2@ can be achieved by increasing the size of the basis sets used for both the adsorbate and Pt cluster atoms.