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 ${\ensuremath{\sigma}}^{(1)}$=2.8(5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}18}$ ${\mathrm{cm}}^{2}$ , ${\ensuremath{\sigma}}^{(2)}$=2.0(7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}50}$ ${\mathrm{cm}}^{4}$ sec, and ${\ensuremath{\sigma}}^{(3)}$ ${=7.9}_{\mathrm{\ensuremath{-}}3.6}^{+6.6}$\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}83}$ ${\mathrm{cm}}^{6}$ ${\mathrm{sec}}^{2}$ . These values are compared with theoretical calculations and other experimental results.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 ${\ensuremath{\sigma}}^{(1)}$=2.8(5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}18}$ ${\mathrm{cm}}^{2}$, ${\ensuremath{\sigma}}^{(2)}$=2.0(7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}50}$ ${\mathrm{cm}}^{4}$ sec, and ${\ensuremath{\sigma}}^{(3)}$ ${=7.9}_{\mathrm{\ensuremath{-}}3.6}^{+6.6}$\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}83}$ ${\mathrm{cm}}^{6}$ ${\mathrm{sec}}^{2}$. These values are compared with theoretical calculations and other experimental results.

Physical Review AJul 1, 198932 citations

R-matrix Floquet theory of multiphoton processes: VI. The negative halide ions

H. W. van der Hart

The R-matrix Floquet approach is applied to study the negative and ions in a light field. Detachment rates are obtained for detachment processes involving up to three photons. The results obtained in the present approach are compared to other experimental and theoretical results. For two- and three-photon processes reasonable agreement with other calculations has been found, while for two-photon detachment the results agree with the experimental cross sections. The three-photon results are in less good agreement with experiment although the larger error bars make accurate comparisons more difficult. The changes in the detachment behaviour for these ions are compared to each other as well as to the detachment behaviour of .The R-matrix Floquet approach is applied to study the negative and ions in a light field. Detachment rates are obtained for detachment processes involving up to three photons. The results obtained in the present approach are compared to other experimental and theoretical results. For two- and three-photon processes reasonable agreement with other calculations has been found, while for two-photon detachment the results agree with the experimental cross sections. The three-photon results are in less good agreement with experiment although the larger error bars make accurate comparisons more difficult. The changes in the detachment behaviour for these ions are compared to each other as well as to the detachment behaviour of .

Journal of Physics B Atomic Molecular and Optical PhysicsJul 28, 199619 citations

Control of Near-Threshold Detachment Cross Sections via Laser Polarization

R. C. Bilodeau, Michael Scheer, Harold K. Haugen

The behavior of near-threshold cross sections for dissociation of a target into a pair of particles, as described by Wigner's threshold law, can depend sensitively on the angular momentum of the particles. In this Letter, we investigate the near-threshold nonresonant two-photon detachment process in the negative ion of gold. The expected s-wave threshold behavior is observed with linearly polarized light. Closure of the s-wave channel is realized by using circular polarization, allowing the first observation of a d-wave threshold. Practical applications are discussed, including extensions which could prove valuable for investigations of negative ions with near-threshold structure.The behavior of near-threshold cross sections for dissociation of a target into a pair of particles, as described by Wigner's threshold law, can depend sensitively on the angular momentum of the particles. In this Letter, we investigate the near-threshold nonresonant two-photon detachment process in the negative ion of gold. The expected s-wave threshold behavior is observed with linearly polarized light. Closure of the s-wave channel is realized by using circular polarization, allowing the first observation of a d-wave threshold. Practical applications are discussed, including extensions which could prove valuable for investigations of negative ions with near-threshold structure.

Physical Review LettersSep 11, 20019 citations

Observation of multiphoton laser-induced collisions (A)

J. C. White, Richard R. Freeman

Journal of the Optical Society of America ADec 1, 19800 citations

{\mathrm{cm}}^{2}

, ${\ensuremath{\sigma}}^{(2)}$=2.0(7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}50}$

{\mathrm{cm}}^{4}

sec, and ${\ensuremath{\sigma}}^{(3)}$ ${=7.9}_{\mathrm{\ensuremath{-}}3.6}^{+6.6}$\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}83}$

{\mathrm{cm}}^{6}

{\mathrm{sec}}^{2}

. These values are compared with theoretical calculations and other experimental results.