Energetics of electron transfer between two ionic centers

6 Energetics of electron transfer between two ionic centers 

We shall now repeat the above calculation for the process (16.10) in which electronic charge is transferred between two atomic centers A and B. In this case 

We consider two ions of radii Ra and 7 positioned at a distance 7 ab between them. We assume that 7 ab A Ra,Rb so that simple electrostatic relations can be used. The relevant fluctuations of the nuclear polarization about state 0 are those that take place in the direction of state 1. The reaction coordinate 6 defines equilibrium states along this direction according to Eq. (16.21), that is, 

So that qoA = a qiA = a and same for B. The same calculation as in Section 16.3.5 is now repeated, however with two modifications. First, the potential 

Second, the required charging work is a sum of the works done to charge both A and B. Even though these two charging processes always occur simultaneously, we may calculate their contribution to the overall charging energy separately. 

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