Abstract

RIOS-REYES, C.H; PONCE-RODRIGUEZ, A; ROMERO-ROMO, M  and  MENDOZA-HUIZAR, L.H. A theoretical quantum study on the distribution of electrophilic and nucleophilic active sites on Cu(100) surfaces modeled as finite clusters. Rev. mex. fis. [online]. 2008, vol.54, n.2, pp.104-111. ISSN 0035-001X.

In this work, it is shown a theoretical quantum study of the active sites distribution on a monocrystalline surface of Cu(100). The copper surface was modeled as finite clusters of 14, 23, 38 and 53 atoms. We performed Hartree-Fock and Density Functional Theory (B3LYP) abinitio calculations employing the pseudopotentials of Hay and Wadt (LANL1MB y LANL2DZ). From calculations, we found a work function value of 4.1 eV. The mapping of the HOMO and LUMO in the frozen core approximation, allowed us finding the electrophilic and nucleophilic active sites distribution, respectively. The results indicated that electrophilic sites on the Cu(100) surface were located on hollow position and its numerical density was 8.6x 10¹⁶ sitescm^-2. From the nucleophilic local softness study, it was found that the nucleophilic sites were formed by a group of atoms and it had a numerical density of 2.4 x 10¹⁶ sitescm^-2. Last results indicated that adsorptions with 2 x 2 and 3 x 3 distributions can be favored onto a Cu(100) surface for the electrophilic and nucleophilic cases, respectively.

Keywords : Active site; B3LYP; pseudopotential; copper; cluster.

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