Mass shift in the mass spectra of TOF-SIMS and the analysis of kinetic energies of the ions

► Apparent mass shifts of the CsI cluster ions were observed in the corrected mass spectrum of CsI measured by TOF-SIMS. ► The kinetic energies of the secondary ions have been determined using post acceleration electrodes. ► The unimolecular dissociation of the cluster ion strongly depends on the relative stability of the cluster ions.