Lifetimes of the negative molecular hydrogen ions:: H2-, D2-, and HD-

The lifetimes of three isotopologs of the molecular hydrogen anion have been measured using an electrostatic ion-beam trap. Much longer lifetimes (up to similar to 2 ms for D-2 (-)) than predicted by the most recent calculation are found, and it is proposed that more than one electronic state contributes to the overall lifetimes of these species.