【摘要】 用密度泛函理论方法研究了EUS2和Eu2S的分子结构、电子结构和成健情况．结果表明EuS2有弯曲构型和直线构型，而Eu2S只有弯曲构型．在S－S和Eu－Eu之间存在化学使．在这两个分子中，Eu和S的价届满足8电子规律，保持其正常价态．第一电离势和原子化能的计算值与实验结果符合较好．相对论效应对分子几何构型和振动基频影响较小，对分子轨道能级顺序和键能有较显著的影响，但旋轨偶合起的作用不大更多还原

【Abstract】 The density functional theory is used to study the molecular structure, electronic structure and chemical bonding of EuS2 and Eu2S. It is shown that EuS2 has both bent and linear configurations, whcreas Eu2S has only the bent one. There is chemical bond between S-S, as well as between Eu Eu atorns. In these molecules, Eu and S are in the normal valent state with their valence shell satisfying the octet rule. The calculated ionization potcntials and atomization ener-gies are in fairly good agreement with thc experimental values. The relativistic effects only slightly influcnce the geometry and vibrational frequency of the molecules while significantly influence the MO levels and the bonding energy, but the spin-orbit interaction does not result in an important effect.更多还原