Spectrum, Kinetics, and Radiation Chemical Yield of Solvated Electrons in Hexamethylphosphoric Triamide

Abstract

The spectrum, yield, and kinetics of solvated electrons in hexamethylphosphoric triamide were investigated by the pulse radiolysis method. The optical absorption band is in the infrared with a maximum at 2200 ± 100 nm. The molar absorptivity at this maximum is (3.2 ± 0.5) × 104 M−1 cm−1, and the oscillator strength for the transition is estimated to be f = 0.7 ± 0.2. A free ion yield of G(es−) = 2.3 + 0.4 solvated electrons/100 eV was determined from the observed yields of anthracene and pyrene radical anions formed by electron attachment.Kinetic studies provided values of the rate constants for the reaction of solvated electrons with anthracene and N2O. The decay mechanism of the solvated electrons in the absence of added solutes was found to be complex, and the half-life (in the range of 2 to 50 μs) was dependent on experimental conditions. A second transient species, absorbing at wavelengths below 500 nm, was observed but not identified. In solutions containing bromide ion the species Br2− was observed. The pulse radiolysis of stable solutions of es−, formed by dissolving sodium metal in HMPA, is also reported.