Calculation and numerical values of the photochemical primary quantum yields

4 CALCULATION AND NUMERICAL VALUES OF THE PHOTOCHEMICAL PRIMARY QUANTUM YIELDS 

The expression suitable for the determination of the primary quantum yield becomes simpler if approximations, valid under certain experimental conditions, are introduced. Such approximations were suggested by Bell and Blacet , who assumed that, at room temperature, elementary reactions (20), (22) and (24) as well as steps (26) and (27) are negligible as compared to the other competitive reactions. With these assumptions, the simple expression 

In case there are no experimental values available for ch3cococ2H3 they have to be calculated from the relation 

Substituting eqn. (32) into (30), and taking into consideration that ch3Coch3(i8) and 0(ch3CO)2 tiay be neglected, we obtain the expression 

Finally, it was suggested that 0co (determined in the presence of iodine) is related to the primary quantum yield by the simple relation 

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