Warm target recoil ion momentum spectroscopy for fragmentation of molecular hydrogen by ultrashort laser pulses

We demonstrate warm target recoil ion momentum spectroscopy for the fragmentation dynamics of the warm hydrogen molecules at room temperature. The thermal movement effect of the warm molecule is removed by using a correction algorithm in the momentum space. Based on the reconstructed three-dimensional momentum vectors as well as the kinetic energy release spectra, different vibrational states of the H₂⁺ ground state are clearly visible and the internuclear separation for charge resonance enhanced ionization of the second electron is identified. The results show adequate accordance with the former experiments using other techniques.