硫在Fe(100)面吸附的第一性原理研究

基于密度泛函理论的第一性原理方法，在广义梯度近似下，计算了硫原子在Fe(100)面吸附的结构和电子性质，并计算了其分子轨道和吸附能.同时讨论了相关吸附性质与硫原子表面覆盖度(0.25-1.0ML)的关系.结果表明：硫原子吸附在H位最稳定，吸附能均随浓度的增加而单调增加；B位吸附的硫原子与Fe(100)表面的距离随浓度非单调变化，在0.5ML时达到最大，是由较高的局域电子云重叠产生的排斥作用所导致的；对比分析吸附前后硫和Fe的s及p电子的态密度，显示了硫化亚铁的生成.

First principles calculation on adsorption of S on Fe(100)

Using the first principles method, which is based on the density function theory (DFT), the structures and electronic properties of S atoms are adsorbed on the Fe (100) surface, and their molecular orbital and adsorption energies were calculated with the generalized gradient approximation. To investigate the atomic geometries and stability with different sulfur coverages for this system, we changed the atomic hydrogen coverage from 0.25 to 1.0 monolayer (ML) using various surface supercell geometries. The results show that the S atom is adsorbed hollow site is stable. The relationship between the adsorption energies and the sulfur coverages was studied, and it is found that the adsorption energies decreased monotonically with sulfur coverages, but it was not as same for the height of S adsorbing above the substrate on B sites. The max of height is the conditions of 0.5 ML. The reason for leading to this phenomenon was a higher local electron cloud overlap repulsion. With partial density of states, we have obtained the interaction of s and p states for S and Fe. It shows that the interaction between the S adsorption on the clean Fe (100) surface does lead to FeS comes into being.