We have studied the ionization and fragmentation of ${\mathrm{SO}}_2$ molecular target in collision with a 1 MeV proton beam using the technique of recoil ion momentum spectroscopy. Two- and three-body fragmentation channels were observed in the Coulomb break-up of ${\mathrm{SO}}_2^{2+}$ molecular ions. Kinetic-energy-release distributions were measured and compared with the available experimental and theoretical data. Dissociation pathways for three-body fragmentation of a ${\mathrm{SO}}_2^{2+}$ ion resulting in (${\mathrm{S}}^{+}+{\mathrm{O}}^{+}$ $+$ O) and (S $+$ ${\mathrm{O}}^{+}+{\mathrm{O}}^{+}$) were studied in detail using Dalitz plots and Newton diagrams. We also obtained the three-dimensional momentum distribution of all fragment particles, including the neutral atom. Correlated angular distributions of the particle momenta were used to infer the geometry of the molecular ion during the fragmentation process.

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• Atomic & molecular collisions
• Atomic & molecular processes in external fields
• Ions
• Molecules