Loading...

Effect of side by side interactions on the thermodynamic properties of adsorbed CO molecules on the Ni(111) surface: A cluster model study

Shamkhali, A. N ; Sharif University of Technology

1078 Viewed
  1. Type of Document: Article
  2. DOI: 10.1080/00268971003716577
  3. Abstract:
  4. The effect of electrostatic interactions on vibrational frequencies and thermodynamic properties of CO adsorbate on the Ni(111) surface is calculated by taking the first and second nearest-neighbour interactions into account. In order to obtain reasonable results, the cluster model of various surface adsorption sites with CO adsorbate is partially optimized, using Density Functional Theory and also the MP2 method for the hcp site. Comparison between DFT and MP2 results shows that DFT results are more reliable for this system. The stretching and bending frequencies of CO adsorbate are calculated using both Partial Hessian Analysis and Cluster-Adsorbate Coupling methods. Stretching and bending frequencies are both shifted by the side by side interactions. The coupling of surface phonons and adsorbate vibrations reduces the side effects. The largest side effects on the vibrational internal energy, isochoric heat capacity, entropy and total Helmholtz free energy of adsorbed CO molecule calculated using the CAC method are found for 0.5 ML coverage. The results of the CAC method are better, but the PHA method can be used as a simple upper bound estimation. The adsorptive phase acts as an intelligent material in such a way that it changes its configuration in order to reduce the side effects
  5. Keywords:
  6. DFT ; Thermodynamic properties ; Vibrational frequency ; Adsorbate vibrations ; Adsorbed CO ; Bending frequency ; Cluster models ; Coupling methods ; Electrostatic interactions ; Helmholtz free energy ; Hessian analysis ; Internal energies ; Isochoric heat capacity ; Nearest-neighbour interactions ; Side by side interactions ; Side effect ; Surface adsorption ; Surface phonon ; Upper Bound ; Vibrational frequencies ; Adsorbates ; Adsorption ; Density functional theory ; Free energy ; Thermodynamics ; Surface structure
  7. Source: Molecular Physics ; Volume 108, Issue 10 , 2010 , Pages 1397-1412 ; 00268976 (ISSN)
  8. URL: http://www.tandfonline.com/doi/abs/10.1080/00268971003716577