Coulomb Explosion Dynamics of Multiply Charged para -Nitrotoluene Cations.

This work explores Coulomb explosion (CE) dissociation pathways in multiply charged cations of para -nitrotoluene (PNT), a model compound for nitroaromatic energetic molecules. Experiments using strong-field ionization and mass spectrometry indicate that metastable cations PNT 2+ and PNT 3+ undergo CE to produce NO 2 + and NO + . The experimentally measured kinetic energy release from CE upon formation of NO 2 + and NO + agrees qualitatively with the kinetic energy release predicted by computations of the reaction pathways in PNT 2+ and PNT 3+ using density functional theory (DFT). Both DFT computations and mass spectrometry identified additional products from CE of highly charged PNT q + cations with q > 3. The dynamical timescales required for direct CE of PNT 2+ and PNT 3+ to produce NO 2 + were estimated to be 200 and 90 fs, respectively, using ultrafast disruptive probing measurements.