Three-Body Dissociation ofH3+

Unexpectedly large cross sections have been observed for the collision-induced excitation of ${\mathrm{H}}_3^{+}$ with subsequent decay to the three-particle state ${\mathrm{H}}^{+}$ + ${\mathrm{H}}^{-}$ + ${\mathrm{H}}^{+}$. The differential (in laboratory angle) cross sections for ${\mathrm{H}}^{-}$ were found to be comparable to that for the final-state formation of ${\mathrm{H}}_2^{+}$ + $\mathrm{H}\mathrm{}\left(2p\right)\mathrm{}$, as determined by a separate coincidence experiment, indicating a strong ionic component to the excited-state wave function.