Photodetachment microscopy to an excited spectral term and the electron affinity of phosphorus

Abstract

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

Accurate Electron Affinity of Iron and Fine Structures of Negative Iron ions

“…The splitting of Fe − ( 4 F 7/2 ) ← Fe − ( 4 F 9/2 ), Fe − ( 4 F 5/2 ) ← Fe − ( 4 F 9/2 ), Fe − ( 4 F 3/2 ) ← Fe − ( 4 F 9/2 ) was determined as 520.9(11), 901.0(14), 1160.8(15) cm −1 by the standard spectroscopic method, the covariance algebra, respectively5152.…”

Comment on “Measurement of the electron affinity of the lanthanum atom”

“…Optimization of the X vector, which contains the targeted spectra and electron affinity, has been described in many detailed articles on the extensive analysis of spectroscopic data [4,5]. The same algebra was precisely used to extract a best-fitting electron affinity from multi-threshold measurements, in the case of Phosphorus [6]. Provided that the dimensions of the involved matrices are not too large, the whole calculation can be easily implemented in a simple spreadsheet.…”

Isotope shift on the chlorine electron affinity revisited by an MCHF/CI approach

“…In combination with improved methods for the measurement of the photoelectron kinetic energies such as photodetachment microscopy [21] and slow-electron velocity-map imaging [22], the technique of laser photodetachment at threshold represents the most precise way of determining photodetachment thresholds experimentally [23]. Amongst the recent applications of photodetachment microscopy, let us cite the first experiment realized in phosphorus [24] with the excitation of the parent neutral atom out of the fundamental spectral term, and the measurement of the electron affinity of selenium with an accuracy of 1 µeV [25] . The possibility of applying the tunable laser photodetachment spectroscopy to the measurement of the isotope shift on the electron affinity has been demonstrated for the first time by Berzinsh et al [26] for the 35,37 Cl isotopes.…”