Summary Competition Between Reaction Channels

7 Summary Competition between Reaction Channels In the previous four sections, quenching mechanisms for the excited noble gas 

In reactions of He with foreign gases, both He(2 and He(2 iS) have been individually studied. In almost all cases, ionization channels have been available and have been considoed to be dominant. For Ne, very few data are availaUe, especially for the resonance states the majority refer to ionization by a beam of metastable atoms of und ned ctHnposition. 

In contrast, energy transfer and dioniluminesoent reaction have been the channels of widest interest for quendiing of the heavier noUe gases. Studies of the V2 states far outnumber those on the higher levels, although, as fw Ne, a small number of molecular beam studies using a mixture of and states has been made. 

In Section 5, E-E energy transfer, as a primary process, has been seen to lead to dissociative excitation as a possible secondary process. Channel (11), collisional dissociation to yield products in their electronic ground states, has been little studied, because of the diflkulty of detecting the product species. Judging by the low emission yields in several reactions of Ar. Kr. and Xe with polyatomic molecules, this must be a major channel, but is iHobably again a secondary decay process for an excited BC intermediate. 

The third major primary reaction chaimd is chemiluminescent reaction, for which a secondary process is again available, predissociation of the excited AX state. The resulting product, X, can also arise from the energy transfer mechanism, through dissociative excitation, a further cautionary note against attempting to deduce the reaction mechanism from the products alone. 

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