We have measured the center of mass motion of the three massive Coulomb-interacting particlesH+,H−,H+in the continuum. Starting with excitedH3+we have experimentally studied the dissociation of this three-body system by determining the final-state energy sharing configurations and mutualH+,H+correlation angles. Each measured triple dissociation event was mapped onto a Dalitz Plot that elucidated the various dynamic processes. In addition to the direct dissociation of excitedH3+into three Coulomb-interacting particles, we have identified intermediate compound states that decay into the observed final-state channel. ©1999 American Institute of Physics.