Electron affinity of Bi using infrared laser photodetachment threshold spectroscopy

High-resolution laser photodetachment threshold (LPT) spectroscopy was made on ²⁰⁹Bi^-. Due to the high resolution of the experiment and large hyperfine splittings of Bi, an analysis including the effects of the hyperfine structure of the neutral and ionic ground states was required, thus describing accurately the observed spectrum.