Single- and multiphoton detachment from storedF−ions

The cross sections for one-, two-, and three-photon detachment from fluorine negative ions have been measured using light at the fundamental and harmonic frequencies of a 1064-nm pulsed neodymium-doped yttrium aluminum garnet laser. The ions were stored in a Penning ion trap, the depletion due to illumination was measured, and the data were fitted to a model for stored ions illuminated by pulsed light. The values obtained for the detachment cross sections are ${\sigma }^{\mathrm{}\left(1\right)\mathrm{}}$=2.8(5)×${10}^{\mathrm{-}18}$ ${\mathrm{cm}}^2$, ${\sigma }^{\mathrm{}\left(2\right)\mathrm{}}$=2.0(7)×${10}^{\mathrm{-}50}$ ${\mathrm{cm}}^4$ sec, and ${\sigma }^{\mathrm{}\left(3\right)\mathrm{}}$ ${=7.9\mathrm{}}_{\mathrm{-}3.6}^{+6.6\mathrm{}}$×${10}^{\mathrm{-}83}$ ${\mathrm{cm}}^6$ ${\sec }^2$. These values are compared with theoretical calculations and other experimental results.