ENERGY EXCHANGE IN PHOTOREACTIONS 



55 



DISTANCE ALONG REACTION COORDINATE 



Fig. 1-19. Typical potential-energy curves for a chemiluminescent reaction occurring 

 as the result of a diabatic process at the top of the ground-state potential barrier. 



DISTANCE ALONG REACTION COORDINATE 



Fig. 1-20. Arrangement of potential-energy surfaces to explain anomalous radiation 

 intensities and ion populations. 



Most flames show chemiluminescence. The usual spectroscopic photo- 

 graph shows very bright Unes or bands superimposed on a background of 

 black-body radiation. The bright lines prove that the corresponding 

 high levels are much more densely populated than they would be in an 

 equilibrium system at the same temperature. Also flames or any rapidly 



