The kinetic shifts were considered. A supporting information figure compares the survival yields obtained using benzylpyridinium positive ions with the sigmoidal curves of the negative mode. The internal energies obtained in the two ionization modes are close, yet slightly lower in positive mode. Positive and negative thermometer ions can be considered as having the same internal energy distribution, as the small difference can be attributed to uncertainties in the RRKM calculations of the kinetic shift, or to the slightly different numbers of DOF.