REARRANGEMENT PROCESSES OF NEGATIVE-IONS IN THE GAS-PHASE - [M-HAL](-) IONS IN HALOGENATED AZOBENZENES, RESONANCE STABILIZATION OF NEGATIVE-IONS

Ionization efficiency curves for [M - X](-) ions from p-XC(6)H(4)N=NC6 H5 molecules (X=F, CI, Br) have been registered in the energy range 0- 9 eV with appearance energies 3.3, 4.1 and 3.2 +/- 0.2 eV, respectivel y. The heats of formation of 17 isomeric C12H9N- ions have been estima ted using isodesmic reactions, The possible mechanism of isomerization of molecule ions leading to various isomeric [M - X](-) ions is repre sented. The resonance stabilization of both negative and positive ions , questioned for negative ions by some workers, was confirmed by measu ring appearance energies of conjugated ions [M - H](-) and [M - (CCl2 + Cl)](-) or [M - Me](+) and [M - CCl3](+) coming from p-MeC(6)H(4)O-R (R= or Me) and 4-Methyl-4-trichloromethylcyclohexa-2,5-dienone, respe ctively,