High power electron spin echo modulation studies of silver atom solvation and desolvation in ice matrices: Geometrical models for silver cation and silver atom aqueous solvation shells

High power electron spin echo modulation patterns have been obtained at 4.2 K and analyzed for presolvated silver atoms produced at 4.2 K in a nonequilibrium environment by radiolysis of deuterated ice matrices containing AgF, and for solvated silver atoms produced by brief annealing at 77 K. The analysis shows that presolvated Ag0 is surrounded by eight equivalent deuterons at 3.1±0.1 Å with zero isotropic hyperfine coupling which suggests a tetrahedral model of four waters with their dipoles pointed away from Ag0 (i.e., a solvated Ag+ geometry). Solvated Ag0 has one deuteron at 1.7±0.05 Å with a 1.8 MHz isotropic hyperfine coupling and seven deuterons at 3.1±0.1 Å with zero isotropic hyperfine coupling. The solvation process appears to occur by rotation of one water around one of its OD bonds with no change in the Ag–O distance.