State selective study of H3+ recombination in Cryo-FALP and SA-CRDS experiments at 77 K

Rate coefficients for nuclear spin state-specific recombination of H3+ ions with thermal electrons were measured using FALP and SA techniques at temperatures 77–300 K. For this purpose H2 gas with both thermal and enriched population of the para nuclear spin configuration was used. Measurements have shown that at 77 K para-H3+ exhibits five times higher binary recombination rate coefficient than ortho-H3+: (1.5 ± 0.4) × 10−7 vs. (3 ± 2) × 10−8 cm3s−1.