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A beam of P− ions produced by a cesium sputtering ion source was photodetached in the presence of an electric field, with a single-mode ring dye laser. Neutral P can be produced at one or the other of the fine-structure sub-levels of its 3s 2 3p 3 2 D o excited term. This is the first atomic photodetachment microscopy experiment with excitation of the parent neutral atom out of the fundamental spectral term. The background electron signal due to ground-state photodetachment notwithstanding, photodetachment microscopy images produced at the excited thresholds could be analysed to provide a measure of these excited-term thresholds with interferometric precision. Starting from the three possible fine-structure sub-levels of P − 3s 2 3p 4 3 P, the five fine-structure thresholds that may be detected, taking the selection rules into account, have been measured. They are combined with the spectroscopic data available in the literature on neutral P to produce an improved experimental value of the electron affinity

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