Book excerpt: The internal energy distribution undergoing collision-induced dissociation (CID) in the cell of a quadrupole ion trap (QIT) mass spectrometer can be characterized by the effective temperature, which would help determine the activation energy and entropy. Here, the relationship in a Bruker QIT has been reexamined based on kinetic measurements at two qz values. An observed linear relationship between ion effective temperatures and resonant activation amplitudes appears qualitatively different from simplified theoretical simulation, which is in agreement with previous results on Finnigan ion trap. However, the normalization process aiming to compensate for the m/z dependency of the required fragmentation energy that is used successfully in Finnigan-geometry traps is not entirely successful for use in Bruker-geometry trans. The calibration determined here roughly indicates the relationship between ion effective temperature, resonant excitation amplitude and ion m/z. However, Successful extraction of the dissociation energetics still requires a better accuracy of the calibration.