Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The concept of hybridization and the principle of maximum overlap are invoked to explain the origin of the Rydberg character of the lowest excited MO of LiH. It is found that the nodal surface of this antibonding MO is not bisecting the bond. The origin of the Rydberg character of the lowest singlet and triplet MO's of the H₂ molecule is studied by means of an energy partitioning. The repulsion of electrons is found to be responsible for the diffuse character of the excited so-called antibonding MO's. The singlet-triplet separation is controlled to a large extent by one-electron contributions.