HARRY COMMONER 



373 





Fig. 9. Variation in ESR signal intensity, with time after cessation and onset 

 of illumination. In this experiment the ESR spectrometer was maintained at a 

 fixed magnetic field and the meter deflection at that field was monitored as a func- 

 tion of time. Temperature, 12.8*'C. The upper curve shows evidence of an 

 "undershoot" effect. 



slow, while the initial rate of decay of component I is rapid. As a 

 result, for a brief period after onset of ilhmiination, the decay process 

 overbalances the increasing signal due to illumination, and the 

 "undershoot" is observed. 



