Paramagnetic Relaxation of Silver Species in γ-Irradiated Frozen Aqueous Solutions

Paramagnetic relaxation of Ag0 and Ag2+ in γ-irradiated frozen aqueous solutions of AgNO3–KF and of Ag0 in γ-irradiated frozen methanol containing AgF was studied at 77°K. (T1T2)1/2 was measured by slow-passage progressive saturation of the absorption signal, and T1 was measured approximately by fast-passage experiments on the dispersion signal which were extrapolated to adiabatic conditions. The spin-lattice relaxation times T1 were directly related to the isotropic coupling constant of the silver species. This suggests that the spin-lattice interaction involves the extent of spin delocalization onto the matrix molecules. The variation of (T1T2)1 / 2 with radiation dose was investigated and interpreted in terms of the spatial distribution of Ag0 and Ag2+. Some spatial nonuniformity exists, but it is not as great as previously found for the trapped-electron precursors of the silver species in 10M NaOH ice.