The fragmentation of propane and deuteropropane molecular ions

Fragmentation of molecular ions as a function of internal energy has been studied for the propane molecules, C3H8, CH3CD2CH3, CD3CH2CD3, and C3D8 using threshold photoelectron–photoion coincidence mass spectrometry. Within the energy range covered (0–6 eV internal energy) the experimental fragmentation curves are compared with those calculated using the quasiequilibrium theory. The general features of the experimental curves are reproduced by the calculations but significant deviations from exact calculations are apparent. The experimental curves for the d2 and d6 propanes show that hydrogen scrambling processes occur and are of sufficient importance that they must be included in future calculations.