Notation Schemes for Electronic Transitions

Various schemes have been proposed to denote the states of a molecule and the absorption bands that correspond to transitions between these states. Some of these schemes are collected in Table 1.2. 

The discussion in the previous section revealed the advantages as well as the disadvantages of the group theoretical nomenclature. 

For cyclic jr-electron hydrocarbons two more schemes, introduced by Clar (1952) and Platt (1949), are widely used. Clar s empirical scheme is based on the appearance of the absorption bands and designates the first three bands in the spectrum of phenanthrene as the a, p, and j3 bands, re- 

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Notation Schemes for Electronic Transitions Intensity and Band Shape 21... 

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