CHx(x=2~4)在Fe(110)表面吸附的DFT研究

采用密度泛函理论与周期平板模型相结合的方法，对物种CHx(x=2~4)在Fe(110)表面的top,hcp,SB和LB位的吸附模型进行了结构优化、能量计算，得到了各物种较有利的吸附位；并对最佳吸附位进行密立根电荷和总态密度分析。结果表明：CH4在Fe(110)表面的最稳定吸附位都是SB位，吸附能别是-38.14 kJ•mol-1，CH3在Fe(110)表面的最稳定吸附位都是top位，吸附能别是-171.78 kJ•mol-1，而CH2在Fe(110)表面的最稳定吸附位hcp的吸附能是-342.43 kJ•mol-1；CH3 和CH2两物种与金属表面成键，属于化学吸附。

Density Functional Theory Study of CHx(x=2~4) Adsorption on Fe(110) Surface

The density functional theory (DFT) and self-consistent periodic calculation were used to investigate the species CHx(x=2~4) adsorption on Fe(110) surface. The adsorption energy, equilibrium geometry of the species CHx(x=2~4) on four possible sites (top, hcp, SB and LB) on Fe(110) surface were predicted and compared . Mulliken charges and density of states analysis of the most stable site have been discussed. It is found that the species CH4 adsorbs feebly on Fe(110) surface with calculated adsorption energy of -38.14 kJ∙mol-1 at the Fe-SB(short-bridge), and the species CH3 adsorbs strongly on Fe(110) surface with calculated adsorption energy of -171.78 kJ∙mol-1 at the Fe-top. However, the CH2 adsorb strongly on Fe(110) surface with calculated adsorption energies of -342.43 kJ∙mol-1 at the hcp. The results indicate that the charge transferring process can be completed by chemisorption between Fe(110) surface and the species. Moreover, the chemical bands can be formed by chemisorption between Fe(110) surface and the species CH3 or CH2.