R-matrix Floquet theory of multiphoton processes: XIV. Multiphoton detachment of

Accurate multiphoton detachment rates for showing the influence of resonances have been calculated using R -matrix Floquet theory. At low intensities the results are in excellent agreement with earlier single-photon detachment calculations and with experiment. At higher intensities the influence of the three-photon excitation of a resonance state on the two-photon detachment rate is shown to be important. It is also shown that the rate for absorption of three photons is substantially enhanced near the frequency which excites the residual lithium atom from the 2p to the 3s state.