Theoretical stu dy of Oxy gen Adsorption on Ni(۱۱۱) Su rface

Oxyg en adsorption on Ni surface provides a model dissociative chemisorption system and a large number of studies of this system have b een conducted using many kin ds of techniques[۱].Comp utational m ethod: In this work the adsorption of oxygen on Ni(۱۱۱) is investigated in p(۲×۲) configuration and oxygen atoms ccupy ۳-f old hollow sites onthe unreconstructed Ni(۱۱۱) su rface corresponding to coverage value of ۰.۲۵ ML by Density Functional Theory (DFT) using ABINIT package. The exch ange-correlation functional is treated within the gener alized gradient approxim ation (GGA ) and Prede w- Burke-E rnzerhof (PBE) functional is appli ed for the structural opti mization an d calculation of adsorptive bond stretching frequ ency[۲]. A slab with ۵ lay ers and ۱۵ Å vacuum selected for these calcul ations as sh own in Fig ure ۱. Also the ۴×۴×۱ an d ۶×۶×۱ k-point mesh are used for the structur al optimization and freq uency calculations, respectively. The plane wa ves with ۴۵ Hartree cut off energy are used for all calculations. For Ni and O atoms, the Trouiller-Martins pseudo potentials are included in the calculations[۳].

کلیدواژه ها:

Adsor ption ، Vibr ational frequency ، DFT ، Oxygen