Multicenter delocalization indices

Bultinck, P Rafat, M Ponec, R., van Gheluwe, B Carbo-Dorca, R and Popelier, P. (2006) Electron delocalization and aromaticity in linear polyacenes atoms in molecules multicenter delocalization index. The Journal of Physical Chemistry A, 110, 7642—7648. 

An interesting comparison between several aromaticity indices (harmonic oscillator model, nucleus-independent chemical shift, para-delocalization index, aromatic fluctuation index, multicenter indices, atoms-in-molecules theoretical indices and graph-theoretical indices) concluded that the most reliable ones are based on electron delocalization (08JCC1543). 

The use of multicenter bond indices as a measure of aromaticity was initially proposed by Giambiagi et al. [95]. These indices measure the extension of the electron delocalization to all centers of the ring which is expected to be large for aromatic systems. Bultinck et al. [96] employed the multicenter bond indices computed from Mulliken-type calculation as a measure of local aromaticity in polyatomic hydrocarbon. Thus, the n-center delocalization index, (A ) can be compnted in the framework of quantum theory of atoms in molecules (QTAIM). 

The amount of electron delocalization has been considered to be a measure of aromaticity. There exist several related aromaticity indices. Giambiagj and coworkers have shown a connection between aromaticity and a multicentre bond index. Bultinck et al7 have used the following multicenter index (MCI) for this purpose,... 

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