PHOTOCHEMISTRY OF CHLOROPHYLL ill vilrO 



9 



flash-photolytic, flash-spectrographic apparatus of Porter and Wind- 

 sor. Figure 1 is a plot of the visible absorption spectrum of chloro- 

 phyll h in pyridine, which was obtained i)y Mr. Fujimori at the 

 University of Minnesota. He has also confirmed Linschitz' result that 

 the triplet state has a broad absorption maxinmm in the near infra- 

 red; about 7500 A for chlorophyll h in l)enzene. 



It has been reasonably well estabhshed that the disappearance of 

 the triplet state occiu's, at least in part, by a bimolecular, self- 



OD 



0.5- 



400 



500 



600 



700 



m>i 



Fig. 1. Absorption spectra of the singlet and triplet states of chlorophyll in 



pyridine (1.3 X 10-« m). 



quenching process in fluid solvents. The study of the reactions of the 

 triplet state has scarcely begun. It is known that molecular oxygen 

 quenches the triplet state efficiently; presumably, at every en- 

 counter. AUylthiourea has little if any effect upon the mean life of 

 the triplet state. Further investigation of these reactions should be of 

 great value in the interpretation of the primary act of photochemical 

 reaction?. 



