RADIOLYSIS OF AQUEOUS-SOLUTIONS OF SILVER POLYACRYLATE - 1ST OLIGOMERCLUSTERS AG6N (N = 1 TO 4)

Aqueous solutions of silver polyacrylate (pH = 10) have been submitted to pulse radiolysis. Through spectroscopic and kinetic observations s everal transient species have been identified: after the classical ste ps leading to Ag0 et Ag2+, a two-band spectrum (300 & 320 nm) has been assigned to an ''Ag2'' cluster complexed with polyacrylate which unde rgoes a polymer reorganisation then a dimerization into ''Ag4'' (295 n m). The rate constants have been determined and a kinetic simulation d escribes the whole process. In identical solutions irradiated under st eady-state conditions with low doses, the successive formation of Ag4( 2+) (280 & 350 nm) and another cluster denoted Aga (295, 480 & 620-800 nm) have been observed, the latter undergoing a reorganisation of its polymer environment during more than 2 months. Owing to the resemblan ce of the spectra and the nature of the precursors, Ag(a) is thought t o be ''Ag4''.