Quartet-doublet conversion

Second, the excited quartet states convert to the doublet state which then acts as a common chemical intermediate. This attractive suggestion, owing partly to to Plane and partly to Schlafer, is plausible because this conversion is known to occur in rigid media. 

Although the formation of HCN + N is not spin-conserved, the formation of the CHN2 radical intermediate is expected to overcome and facilitate the doublet — quartet conversion. At room temperature, the CHN2 adduct probably disappears by secondary reactions with active species present in the system. The effects of both temperature and pressure on the rate of this important reaction will be thoroughly investigated in the near future. 

At the first collision (f=0) where the Q-D conversion is prohibited at the close pairs because of a large 7 value, the quartet and doublet pairs have equal population (p)... 

In the case of the sterically more demanding l-benzylmethylamino-8-dimethylamino-naphthalene (119), the conversion of the NMe2 group singlet into the doublet occurs at —38 °C simultaneously, the methylene group singlet splits into a quartet. In this case, the AG value is nearly doubled. Similar dynamic processes of different complexity... 

Fig. 4.9 State diagram for an hexacoordinate Cr(III) amine complex. Excitation leads to Franck Condon states that decay by internal conversion. Both direct and reverse intersystem crossing to the lowest quartet state Q° occur. This slate emits or decays non-radiatively fe, k-2). The lowest doublet D° may be formed by this way. From [145, 146]...

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