  Field evaporation from ionic or covalently bonded materials often leads to
the emission of molecular ions. The metastability of these molecular ions,
particularly under the influence of the intense electrostatic field (1010
Vm-1), makes them prone to dissociation with or without an exchange of energy
amongst them. These processes can affect the analytical performance of atom
probe tomography (APT). For instance, neutral species formed through
dissociation may not be detected at all or with a time of flight no longer
related to their mass, causing their loss from the analysis. Here, we evaluated
the changes in the measured composition of FeO, Fe2O3 and Fe3O4 across a wide
range of analysis conditions. Possible dissociation reactions are predicted by
density-functional theory (DFT) calculations considering the spin states of the
molecules. The energetically favoured reactions are traced on to the multi-hit
ion correlation histograms, to confirm their existence within experiments,
using an automated Python-based routine. The detected reactions are carefully
analysed to reflect upon the influence of these neutrals from dissociation
reactions on the performance of APT for analysing iron oxides.
