Fragment Correlation in the Three-Body Breakup of Triatomic Hydrogen

We investigate the fragmentation of the triatomic hydrogen molecule ${\mathrm{H}}_3$ in a triple-coincidence experiment. A single rovibronic state of ${\mathrm{H}}_3$ is laser prepared and its breakup into three hydrogen atoms $\mathrm{H}\left(1s\right)$ is monitored by time- and position-sensitive multihit detectors. For each triple hit, the momentum vectors of the three $\mathrm{H}\left(1s\right)$ fragments are determined. The sixfold differential cross section of the fragment momentum components in the center-of-mass frame is found to be highly structured and to depend sensitively on the ${\mathrm{H}}_3$ initial electronic state.