Electron capture by tetra- and di-chlorobenzene molecules. Comparative studies by position annihilation and ODESR methods

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.