Temperature effects in mass spectrometry. Estimation of thermal energies of organic molecules

Thermal energies of gaseous organic molecules, relevant to unimolecular dissociations of odd‐ and even‐electron ions, are estimated by ab initio/RRHO and empirical calculations. Thermal energies can be estimated with good accuracy by integration of molar heat capacities obtained from quadratic least‐squares fits. Thermal energies in gaseous n‐alkanes, alkanols, cholesterol, polyethylene glycols and oligopeptides are calculated and compared with estimates based on the equipartition principle.