Electron Capture by Tetra- and di-Chlorobenzene Molecules

Experiments on inhibition and anti-inhibition of Ps formation and also on optical detection of ESR spectra in squalene solutions with 1,2,4,5-C6H2Cl4 and p-C6H4Cl2 have demonstrated the presence of short-lived molecular radical-anions (products of the spur electron capture by additives), their lifetimes being longer than roughly 10 ps and shorter than 10–30 ns. The cross section of electron capture by p-C6H4Cl2 in squalane is nearly one-tenth of that by 1,2,4,5-C6H2Cl4 and CCl4 at concentration ⩽ 0.02 M, while 10% of the electrons cannot be trapped even at 0.25 M p-C6H4Cl2. Probably the electrons in the high-electric-field (0.3–3 MV/cm) regions of the spurs cannot be effectively captured by p-C6H4Cl2, which is a shallow electron trap. Similar effects of the high electric fields of the charged spur series seem to influence the Ps formation appreciably, along with the other effects discussed in previous papers. Several new results can be predicted, by use of this interpretation. Both methods employed are emphasized to be selective with respect to geminate spur particles.