Laser ionization and time-resolved ion collection in cesium vapor

Cesium atoms are ionized by resonant two-photon pulsed laser absorption. The ion collection is investigated when the application of the collecting electric field is time delayed with respect to the laser pulse. It is shown that the time evolution of the atomic ion density is governed by a conversion of atomic ions to molecular ones. Owing to the large molecular recombination coefficient the ion density decreases exponentially. The conversion rate constants for collisions with cesium or argon atoms have been determined.