ESR studies of a new reactive species produced in γ-ray irradiated solid para-H2 at 4.2 K

A new reactive species in γ-irradiated solid p-H2 has been studied by ESR. When p-H2 is irradiated at 4.2 K with γ-rays, a small amount of the new reactive species which shows doublet ESR lines with a separation of 12.4 G is observed in addition to intense peaks of H atoms. The yield of the new species is 0.0001 G-unit. The new species decays in several hours upon storage of the irradiated solid p-H2 at 4.2 K. The doublet lines were interpreted in terms of an ion-pair of an electron and a hole (et−…p-H2+) separated by 13 Å.