An investigation of electron thermalization in irradiated gases using CCl4 as an electron energy probe

Abstract

The attachment of electrons to CCl4 has been studied in pulse irradiated argon and its admixtures with several atomic and molecular compounds under conditions where the timescale of attachment is comparable with that of electron thermalization. Using the known energy dependence of the rate constant for attachment, the resulting complex electron decay kinetics have been quantitatively related to the energy relaxation process. Values of the energy exchange rate coefficient Ku defined by the relationship d?/dt = −Ku⋅[? − (3/2) kT]⋅NM have been determined for 18 compounds of varying complexity and dipole moment. The values of Ku found encompass the range from 1.3×10−13 cm3 sec−1, for argon, to 1.5×10−8 cm3 sec−1, for acetone. The results are compared with energy exchange parameters available from other sources. Thermalization times and ranges of electrons in irradiated gaseous and liquid systems are calculated and their relevance to radiation chemistry is discussed.