High resolution molecular photoelectron spectroscopy. III. Acetylenes and aza-acetylenes

The 584 $\overset{\circ}{\mathrm A}$ (21.22 eV) photoelectron spectra of the following linear unsaturated molecules are reported: acetylene, dideutero-acetylene, hydrogen cyanide, deuterium cyanide, diacetylene, dideutero-diacetylene, cyanoacetylene, cyanogen, dicyanoacetylene, methylacetylene and dimethyltriacetylene. The ionization potentials of the molecules, and the vibrational fine structure observed in many of the bands, are discussed.