CO/MgO(001) at different CO coverages: a periodic ab initio Hartree-Fock and B3-LYP study

摘要: Abstract The adsorption of CO at various coverages on the regular MgO(0 0 1) surface has been studied using a rigorous ab initio approach based solution periodic Schrodinger equation both Hartree–Fock and DFT levels. crystal orbitals are expanded in Gaussian atomic Coulomb exchange series treated rigorously as implemented crystal-98 computer code, ensuring correct behavior electric field outside crystalline surfaces. For calculations, B3-LYP functional coupled with basis sets high quality for calculations have adopted. Three different (namely 1×2(CO×Mg), 1×4 1×8) considered. Because very small binding energies (BEs), careful analysis effects set superposition error well computation harmonic frequency shift numerical procedures better than past carried out. Comparison results obtained CO/Na+ CO/CO2 complexes also made order to clarify bonding ionic Neither charge transfer nor polarization play significant role, weak BE from large cancellation between electrostatic repulsion components formerly suggested by accurate cluster embedded total-ion model potential. Our best energy still underestimated respect most updated experimental data good agreement calculations. disagreement experiment seems suggest that dispersive contribution BE, unfortunately not accounted Hamiltonians encoded available codes, may an important role reconcile simulation those experiment.