中文摘要：

采用基于密度泛函理论的平面波赝势方法的第一性原理计算，对过渡金属Fe元素进行自旋极化的总能最计算，能量计算精度取为平均每个原子0．01eV．通过分析分波能带展宽与能带电子对总能量的贡献，讨论了在不同压强范围下第一性原理计算时Fe原子芯态与价态的合理划分，结果显示，当压强增加到约140GPa时，3p电子对总能的贡献将不能忽略，而在地心压强下，3S电子的贡献可以忽略．

英文摘要：

We performed first-principles calculation for the body-centered cubic iron based on density-function theory, employing the pseudopotentionals and plane-wave method. We set the computational precision of the energy of one atom to 0.01 eV and make the spin-polarized total-energy calculation. The calculated results show that the 3p state should be treated as valence state when pressure is higher than 140 GPa, while the contribution to the total energy due to the dispersion of 3s state can be ignored for the whole range of earth＇ s core condition.