Departamento de Química FisicayAnalítica, Facultad de Química, Universidad de Oviedo, 33006, Oviedo, Spain.
Unidad Académica de Ciencias Básicas e Ingenierias, Universidad Autónoma de Nayarit, Tepic, 63155, México.
Chemistry. 2019 Sep 18;25(52):12169-12179. doi: 10.1002/chem.201902369. Epub 2019 Aug 23.
Real-space tools were employed to show that the chemical bonding scenario used routinely to understand ground states lacks the necessary flexibility in excited states. It is shown that, even for two-center, two-electron bonds, the real-space bond orders have exotic values that have never been reported. The nature of these situations was uncovered by using electron-counting techniques that provide an appealing statistical interpretation of bonding descriptors, together with simple physical models. Bond orders greater than one as well as negative bond orders for a single bonding electron pair emerge in situations in which the electrons in the pair show a gregarious (bosonic) instead of the usual lonely (fermionic) behavior. In the first case the gregarious pair is intra-atomic, whereas the coupling is interatomic in the second. A number of examples are used to substantiate these claims.
采用实空间工具表明，用于理解基态的化学键合方案在激发态中缺乏必要的灵活性。结果表明，即使对于双中心、双电子键，实空间键序也具有从未报道过的奇异值。通过使用电子计数技术揭示了这些情况的本质，该技术为键描述符提供了吸引人的统计解释，同时还结合了简单的物理模型。在电子对表现出群居（玻色子）而不是通常的孤独（费米子）行为的情况下，会出现键序大于 1 以及单个键合电子对的负键序。在第一种情况下，群居对是原子内的，而在第二种情况下，键合是原子间的。使用了一些例子来证实这些说法。
