Non-ergodic dissociative valence double ionization of SF₆

The dissociative double ionization of sulphur hexafluoride, SF₆, in the ionization energy range from threshold up to 48.4 eV has been examined in detail using a multiple coincidence electron-ion technique. The results are interpreted by comparison with molecular dynamics simulations, high level molecular structure calculations and with a statistical model of the ion breakdown. Comparison between the experimental breakdown pattern and the pattern derived on the basis of statistical theory indicates that the energy redistribution required for fully statistical behaviour is incomplete on the timescale of the dissociation reactions of [Formula: see text], suggesting that the molecular size at which ergodic behaviour becomes dominant is larger for doubly and multiply charged ions than for neutral and singly ionized molecules.