Abstract: | The origin of the hydrogen radical lost in the ionization chamber from the molecular ion of 2-methylindolizine has been studdied by examination of the spectra of four specifically deuterated species. Hydrogen loss involves preferentially a hydrogen from the methyl substituent but also one of the hydrogens of either ring, especially those of the 5-membered ring. The HCN elimination from the metastable M? H˙]+ ions was studied using a linked scan method; the results are consistent with loss of identity of all the hydrogen atoms of the precursor ion, which implies an extensive reorganization prior to fragmentation. |