Mechanisms of ion ejection from liquid beam under irradiation of laser by simultaneous detection of ions produced inside a liquid beam and ejected into a vacuum

An aniline solution in l-propanol, or a pure ethanol Liquid, was introduced into vacuum as a continuous liquid flow (liquid beam) and was irradiated w ith a 266-nm laser. Ions were produced in the liquid beam by multiphoton ab sorption and partially ejected into the vacuum. The abundance of ions remai ning inside the liquid beam and that ejected in the gas phase were measured simultaneously by using an inductive detector and a time-of-flight mass sp ectrometer, respectively, as a function of irradiation-laser power. The res ult is explained by the Coulomb ejection model for the ion ejection from th e liquid surface. The essential feature changes slightly with the rate of t he ion diffusion with respect to that of the ion ejection.