Rule, Franck-Condon

A summary of all the evidence171 indicates, but does not prove, that 02 is the c1 - state of Oa. The excited molecule must contain sufficient energy to react with an unexcited 02 to produce 03 plus O atoms some of the time. Thus the a1 A9 and states are eliminated unless they contain a large excess of vibrational energy. However, if this were the case, 02 should be vibrationally deactivated rather efficiently by collision, contrary to the findings of Heicklen and Johnston.86 Furthermore, the Franck-Condon rules tend to favor the formation of electronic levels with small amounts of vibrational energy. 

Edward Condon (1902-1974), American physicist and one of the pioneers of quantum theory in the United States. In 1928, Condon and Gurney discovered the tunneling. More widely known is his second great achievement-the Franck-Condon rule (discussed later in this chapter). During the WW2 he participated in the Manhattan project. 

Franck-Condon rule). Whatever falls (.vertically, because of the Franck-Condon rule) on the REP state as a result of fluorescence dissociates because this state is repulsive. The kinetic eneigy of the dissociation products depends on the internuclear distance R when the fluorescence took place (i.e.. on the length of the slide the system had down the REP). How often such an R occurs depends on Therefore, investigating the kinetic energy of the dissociation products gives... 

I he change of electronic state takes place so fast that the nuclei do not have enough time to move. Thus the positions of the nuclei in the excited state are identical to those in the ground state (Franck-Condon rule). 

The interpretation of these facts can be given with the aid of fig. 58 and the Franck-Condon rule discussed in section 25. Most of the molecules at room temperature will be present in the vibrational level t " = 0 of the ground state. Now if... 

The point FC in Fig. 6.15 shows the very essence of the Franck-Condon rule -a vertical transition. The corresponding nuclear configuration may differ quite significantly from the nearest potential energy minimum M in the excited state PES E-). In a few or a few tens of femtoseconds, the system slides down from P to the... 

Franck-Condon rule (p. 266) funnel effect (p. 266) non-radiative transitions (p. 266) photochemical reaction (p. 266) muon catalyzed nuclear fusion (p. 268) split nucleus effect (p. 270)... 

The product half of the excited state hypersurface runs up to the reactant half of the ground state hypersurface and vice versa. This means that photoexcitation (following the Franck-Condon rule this corresponds to a vertical excitation) means a profound change the system looks as if it has already reacted (photoreaction). 

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