Springer Online Journal Archives 1860-2000
Abstract Electrons produced in a sodium effusive beam irradiated by pulsed laser light have been energy-analyzed. For resonant excitation of the atoms to the 3p state, we have studied associative ionization of excited Na(3p) (AI), Penning ionization (PI) and photoionization of highly-excited Na(n l),n l=3d, 4p, 5s, 4d/4f, by measurements of electron energy spectra. Our interpretation of the spectra is supported by a numerical analysis of the data which leads to estimates of the cross sections compatible with values previously measured in other experiments. Off-resonance ionization is considered at a particular wavelength. It is presumed to involve laser-excited dimers Na 2 ** . Spectra show that highly-excited atoms are produced by photodissociation of Na 2 ** or from Na 2 ** -Na collisional energy transfer, and that these atoms support the dominant off-resonance ionization channel in our laser excitation conditions.
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