An anisole-ethanol solution was introduced into vacuum as a continuous
liquid flow (liquid beam), and the molecules in the liquid beam were
ionized by laser two-photon ionization. Ions ejected from the liquid b
eam were extracted by applying a pulsed electric field for the measure
ment of time-of-flight mass spectra of the ions. The intensities and p
eak profiles of the ions were measured by varying the delay time from
the laser ionization to the pulse extraction of the ions at different
laser powers. All the ions observed have almost the same velocity (app
roximate to 700 m s(-1)) and need approximate to 1 mu s to leave the l
iquid beam after laser irradiation. This finding implies that each pho
toion forming a solvation structure with almost the same number of sol
vent molecules is expelled from the liquid surface by Coulomb ejection
and is dissociated into a cluster ion outside the influence of the Co
ulomb potential. The rate constants for ion ejection were determined.