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Exotic Bonding Regimes Uncovered in Excited States
Author(s) -
CasalsSainz José Luis,
JaraCortés Jesús,
HernándezTrujillo Jesús,
GuevaraVela José Manuel,
Francisco Evelio,
Pendás Ángel Martín
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201902369
Subject(s) - excited state , electron , chemical bond , flexibility (engineering) , space (punctuation) , bond , simple (philosophy) , interpretation (philosophy) , physics , atomic physics , statistical physics , coupling (piping) , chemical physics , quantum mechanics , theoretical physics , computer science , materials science , mathematics , statistics , philosophy , finance , epistemology , economics , programming language , operating system , metallurgy
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.