“…However, although an impressive amount of photoionization data has been obtained on atoms (Kjeldsen, ), little has been reported so far on molecular targets. Hitherto, studies have only been reported on CO + (Andersen et al, ; Hinojosa et al, ), and some fullerenes molecules (Scully et al, ; Kilcoyne et al, ). The difficulty in studying relatively small molecular ions in a merged‐beam experiment is that often the doubly charged molecules are not stable with respect to dissociation.…”