| In recent years, the surface system have attracted much attention in the science community for their value of applications. In the field of catalysis, it not only can be used as a catalyst, also can be used as the carrier of catalyst. In the field of molecular electronic, the molecular film formed on the surface can be used for making the electronic devices or electron emission devices. Phthalocyanine, as a kind of aromatic molecules with a special structure, has a great application prospect. Metal phthalocyanine has been widely used because of it’s good performance in the electrical conductivity, chemical catalytic, photoelectric effect and so on. The study on the metal phthalocyanine became the focus of the science community.With the development of the experimental technology, we can have a deeply understanding about the system of the metal phthalocyanine on the surface with the help of the high performance experimental instrument. But due to the restriction of the experimental conditions, we still can not understand the process of the adsorption on the atomic scale, so first principles calculation is particular important. There are some problems during the calculation, for example the results for the same system from different researchers are not consistent.First-principles calculations for metal-phthalocyanines (MPc, M=Co, Fe, H2) adsorbed on Au(111) surfaces with LDA, PW91, and optB86b-vdW functionals are performed. The adsorption energies, adsorption distances, potential energy surfaces, electron transfer properties, and the migration barriers are calculated and compared with the reported experimental data. Our results show that, while PW91 functional is obviously not suitable for MPc/Au(111) systems due to its intrinsic short comings, LDA and optB86b-vdW functionals give more reliable results. The optB86b-vdW functional has overall the best performance among the three functionals, which indicates that the van der Waals interactions play key roles in such adsorption systems. |
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