应用相对论理论(Dirac)来计算 C、O、S、Se、Te、Sm和Pu原子的相对论和非相对论的电子状态和能量，比较相对论和非相对论的能量差别后得到：如果以 O 原子的相对论和非相对论能量差为1，则 S、Se、Sm和Pu原子的相对论和非相对论能量差分别为 17.5、479、6 781 和 46 166。就钚和氧相比，质量的相对论效应增加46 166倍。Pu的相对论的和非相对论的能量的差占总能量的 8.72 %，所以对重元素，应用相对论的计算是很必要的。

The present work devotes to the calculation of relativistic and non-relativistic electronic state and energy for atoms C, O, S, Se, Te, Sm and Pu. In comparison between the relativistic and non-relativistic electronic energy,it is concluded that if energy difference of relativistic and non-relativistic electronic energy for O atom is supposed as unit, then there will be 17.5,479,6 781 and 46 166 for S,Se,Sm and Pu ,respectively. The energy difference of relativistic and non-relativistic electronic energy for Pu is about 8.72 % of its total energy. Therefore, it is quite necessary to calculate heavy atoms using relativistic theory.