Electron Impact Studies of Hydrazine and the Methyl-substituted Hydrazines1

Relative abundances and appearance potentials are reported for the principal ions in the mass spectra of hydrazine, monomethyl-, 1,1-dimethyl-, 1,2-dimethyl-, trimethyl-, and tetramethyl hydrazine. Heats of formation of the radical ions and probable ionization-dissociation processes are tabulated consistent with the calculated energetics. Molecular ionization potentials computed by the use of antisymmetrized orbitals are compared with experimental observations. Heats of formation of various hydrazyl and methyl amino radicals obtained from the appearance potential data permit a determination of bond strengths in the methyl hydrazines and other nitrogen-containing molecules. Ionization potentials of various hydrazyl radicals are calculated and found to be surprisingly low. A characteristic decrease in ionization potential with increased methyl substitution is noted.