The effect of a magnetic field on geminate ion-pair recombination

5 THE EFFECT OF A MAGNETIC FIELD ON GEMINATE ION-PAIR RECOMBINATION 

In Chap. 6, Sect. 4, the effect of a magnetic field on the probability and the rate of (neutral) radical radical-pair recombination was discussed. Much of this can be extended to the case of ion-pair recombination. There are three means by which spin correlation may be lost [403]. 

S0 or T0 with 7V is reduced. Consequently, the distribution of singlet and triplet states in a radical ion-pair approaches 1 1 as the external magnetic field increases ( 0.1 T). 

Striking evidence for the role of the hyperfine interaction on the time dependence of ion-pair recombination was found by Brocklehurst [56, 409]. He ionized a solution of p-terphenyl in decalin (benzene, squalane etc.) with 90Sr (3 particles and observed the time dependence of the fluorescence intensity. When the experiment was repeated, but with a magnetic field ( 0.16 T) applied, the fluorescence intensity was enhanced by approximately 40% after about 10—20 ns. The magnetic field splits the triplet levels so that only T0 can mix with S0 and the initial singlet 

---