Stepwise photoionization of 1,2-dimethoxybenzene vapor

Processes of stepwise ionization of 1,2-dimethoxybenzene vapor by radiation in the range 295-275 nm were studied by the techniques of total current sp ectroscopy, mass spectrometry, electronic absorption spectroscopy, and thre shold electron spectroscopy. A two-step ionization process via the first el ectronically excited state of the molecule yielding the molecular ion was f ound to prevail at an average laser radiation intensity less than 10(6) W/c m(2). Molecular ions possess a considerable (up to 1 eV) vibrational excita tion energy. As the radiation intensity increases, the progressively strong er and deeper degradation takes place via dissociation of molecular and, pr obably, fragment ions due to absorption of at least one additional photon.