dissociation method sustained off-resonance irradiation SORI MS MS:1000282 A technique associated with Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry to carry out ion/neutral reactions such as low-energy collision-induced dissociation. A radio-frequency electric field of slightly off-resonance to the cyclotron frequency of the reactant ion cyclically accelerates and decelerates the reactant ion that is confined in the Penning ion trap. The ion's orbit does not exceed the dimensions of ion trap while the ion undergoes an ion/neutral species process that produces a high average translational energy for an extended time.