Singlet stale excited

This dialog box also contains the option for specifying that the molecular system ism the first excited singlet stale (Next lowest or the Lowest electronic state. 

Aromatic nitriles are strong oxidants in their excited states (see Table I). Since they fluoresce strongly, the involvement of the singlet states can be easily proved by application of fluorescence quenching techniques. In all of the tested cases, it has been found that the Stern Volmer constant obtained from fluorescence analysis and that obtained from the double reciprocal plots of reaction quantum yield vs. quencher concentration are nearly equal, thus proving that the singlet stale is actually involved In the photochemical reaction. Actually it has been observed that a AG < 0 and polar solvents are necessary (although not sufficient, see Section 3) conditions for the photochemical proc-... 

The Stale Correlation Diagram (SCD) approach introduced by Shaik and Pross96 appears similar in some respects. However, the LUMO, HOMO and the first two exciled stales are considered, (refer Figure 1.5)4,53 Thus, if we consider the interaction of the radical with the olefin in its ground (singlet) state (R + C=C ) and excited (triplet) state (R + C=CJ) and two charge transfer... 

Table 1.2 Energies of excited singlet and iriptei stales...

The product of step 3 of Scheme 7.1 must be regarded as an excited stale R of R. R can. in principle, be an electronic singlet or triplet In either ease, it is a kind of difadical. liming a substantially localized election at ( -1 with a partner tof either spin) in the aromatic rings. 

Most of the competing pathways for racemization and retention in. Scheme 7.1 would not be expected to produce such a limit. The pathway that could best account for it may be the singlet version of 1-3-4. Here partial racemization would occur in step 4, where X" has been lost from the reactant. The rales of racemization and passage from the initial excited stale "R to the ground slate could... 

FIGURE 6-3 Spin onentalions in singlet ground and excited slates and triplet excited stale. 

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