Nanosecond Pulse Radiolysis of Ammoniacal Solutions of Silver Salts

Radiolysis of silver ion solutions in ethylene glycol: solvated electron and radical scavenging yields

“…From the slope, the bimolecular rate constant for reaction (1) between e À solv and Ag + is found to be k 1 =(3.370.1) Â 10 9 dm 3 mol À1 s À1 . This constant is much lower than the rate constants for the same reaction in water: 3.6 Â 10 10 dm 3 mol À1 s À1 (Janata et al, 1994), in liquid ammonia: 1.5 Â 10 12 dm 3 mol À1 s À1 (Farhataziz et al, 1976), or in methanol: (2.670.6) Â 10 10 dm 3 mol À1 s À1 (Mostafavi et al, 2002). The dielectric constant of ethylene glycol ( s ¼ 37) is in the range of the values for other alcohols or ammonia.…”

“…4. The increasing absorbance at 350 nm is assigned to the silver atom Ag 0 whose spectrum was studied in numerous solvents (von Pukies et al, 1968;Farhataziz et al, 1976;Mostafavi et al, 2002). During the first 100 ns, the absorbance increase at 350 nm is nearly correlated to the absorbance decay of the solvated electron at 575 nm according to reaction (1).…”

“…During the first 100 ns, the absorbance increase at 350 nm is nearly correlated to the absorbance decay of the solvated electron at 575 nm according to reaction (1). After a maximum at around 200 ns (A 350, max =0.5), the absorbance of Ag 0 decreases, due to reaction (3) with silver cations producing the charged dimer Ag 2 + , which is also known in water (Janata et al, 1994), ammonia (Farhataziz et al, 1976), and methanol (Mostafavi et al, 2002). At much longer time, in the range of seconds, the progressive coalescence of silver atoms and Ag 2 + into clusters through reaction (4) is observed at 380 nm (Fig.…”

Transients and specific rates of some reactions of the solvated electron with inorganic ions in liquid ammonia investigated by nanosecond pulse radiolysis at 23.degree.C

“…ka For values of kd given earlier in the discussion and values of kobsd given in Table I, values of ha were calculated for various reactions of earn-with metal ions, and are given in Table I. For a metal ion (charge z + ) dissolved in liquid ammonia, M,,l*+, the reaction of earn-is MsolZ+ + earn-+ Msol(z-l)+ (6) The standard free energy change, AF,", of reaction 6, AF" (Msoi(*-')+), AF" (MsolZ+), and AF" (earn-) [the standard free energies of formation of Msol(z-l)+, Mso12+, and earn-, respectively], are related by AF," + AFo(eam-) = AFo(MsO1(Z-l)+) -AFo(MsolZ+) (7) Thus a relationship between AF," and ha can directly be explored in terms of AF," + AF" (earn-), and ha. At 25 "C, from values of free energies of formation of various ions and neutral atoms dissolved in liquid ammonia (cf.…”

Molecular dynamics simulations of the temperature and density dependence of the absorption spectra of hydrated electron and solvated silver atom in water

“…An indication of the influence of the atom-solvent interaction is given by the solvent dependence of the optical absorption spectra in solution. In ammonia, the absorption spectra of silver atoms and dimers were observed at two different temperatures: 296 K [22] and 223 K [23]. The maximum of absorption band was found at 435 nm and 450 nm, respectively.…”