Multiphoton And Electron-Impact Ionization Of Azirines .2. 2,3-Diphenyl-1-Azirine At 248 Nm And 193 Nm

Multiphoton ionization of 2,3-diphenyl-1-azirine is reported for nanosecond laser excitation at 248 and 193 nm and compared with electron impact ionization. The dependence of the ion intensity on the laser intensity shows that the formation of the parent ion and some of the more prominent fragment ions require the absorption of two photons per molecule. Other fragment ions are produced after the absorption of three photons. The results of the absorbed photon energy are corroborated by ionization and appearance energies obtained on calibrated electron impact ionization. Pure metastable ion spectra were obtained both by the defocusing method and by direct analysis of daughter ions produced by electron impact ionization and also by multiphoton ionization. The multiphoton absorption is shown to proceed via two different excitation pathways. A complete ionic decay scheme is given.