Computer modeling of data from pulse radiolysis studies of aqueous solutions containing scavengers of spur intermediates

Abstract

With the calculations reported here, all of the data from a comprehensive study of the kinetics of hydrated-electron decay in the 14-MeV-electron pulse radiolysis of pure water and aqueous solutions have been modeled within experimental error. The overlapping-spur model utilized employs a constant-energy fraction (0.2) of high, constant spur density regions (representing blobs/short tracks) and another constant-energy fraction (0.8) of a low, variable spur density region (representing isolated spurs) whose spur density is proportional to the pulse dose. The model also contains a new hydrated-electron probability density distribution function with the maximum in the probability density displaced from the center of the spur. Adjustments made to fit experimental data from different aqueous-solution pulse radiolysis studies have been minor. Hydrated-electron decay kinetics have been modeled within experimental error for a variety of scavengers of transient reactive intermediates originating in the spur. Thus, this new spur model has been successfully tested against experimental data for 14-MeV electrons over a wide range of pulse doses (0.5-80 Gy), time regimes (10/sup -11/-10/sup -5/ s), and types of scavengers of the major spur transients (e/sub aq//sup -/, .OH, and H/sup +/).