The spectra of fragmentation of molecules under the action of pulsed laser radiation or ion beams are studied in the sudden-perturbation approximation. By the example of the fragmentation process of the propane molecular ion [C3H8]+, it is established by calculating the most significant potential-energy surface cross sections along the reaction pathway that there is a correlation between the probability of formation of ionic fragments and the breaking energetics of individual chemical bonds. A complex rearrangement of atoms in the methane detachment process is established. The fragmentation spectra are attributed to protons with an energy of approximately 10 keV.