Negative ion mass spectra of some phenalenone derivatives

Temperature dependence of the negative ion mass spectra (NIMS) of six phenalenone derivatives has been investigated using a mass spectrometer with the static magnetic field mass analyzer. The dissociative attachment cross-section and the mean lifetime of the molecular NI's decreases approximately exponentially with the temperature rising, and the dissociative attachment cross-section of fragment ions generally increases with temperature. The mean lifetime of the molecular anions is at least tens of microseconds for all the investigated compounds.