in ion-source of mass spectrometer; not isolated, detd. by MS;
参考文献
Koppen, Petra A. M. van; Jacobson, Denley B.; Illies, Andreas; Bowers, Michael T.; Hanratty, Maureen; Beauchamp, J. L.
Journal of the American Chemical Society, 1989 , vol. 111, # 6 p. 1991 - 2001