原子和分子片的洪特多重度规则的量子化学解释

Hund's multiplicity rule for some atoms and molecular fragments a quantumchemical UHF interpretation

以7种原子和5种分子片物种为例,采用UHF/6-311++G(3df,2p)方法,优化了它们的电子在垂直和绝热跃迁过程中的构型,计算了相同电子组态,不同低自旋态和高自旋态物种的最低单点能量(ES,ET);比较了它们的最高占据轨道能量(低态能εS-HOMO,高态能εT-HOMO).结果发现,无论是绝热还是垂直变化过程,也不论键距长短,总会存在如下关系:ΔεHOMO=εS-HOMO-εT-HOMO>0,ΔES-T≈ΔεHOMO>0.最后证明了这些关系式.

Seven atoms （neutral, cationic, anionic）, and five species of molecular fragment （with the two nuclear electronics, heteronuclear two electronics, two electronic multi-cores, multi-core multi-electronics） were taken as examples, their structures were optimized by UHF/6-311 ＋ ＋ G（3df, 2p ） method for their vertical and adiabatic process in the transition process. Single point energy （ Es, ET） for low and high spin state with the same electronic configuration were calculated and compared with their highest occupied orbital energy （εS-HOMO; εT-HOMO） . Our Results showed that the equtafions △εHOMO=εS-HOMO-εT-HOMO〉0,and △ES-T≈△εHOMO〉0 are independent for vertical, or adiabatic process, or bond length.