Measurement of the electron affinity of lead and its isotope shifts

The electron affinities of the primary isotopes of lead have been precisely measured using photodetachment threshold spectroscopy. The relative cross sections for photodetachment from Pb− isotopes 206, 207, and 208 were observed using a tunable midinfrared optical parametric oscillator-amplifier to determine the ground-state binding energies. The isotope-averaged electron affinity of Pb was measured to be 356.723(7) meV, in excellent agreement with previous measurements. Furthermore, the isotope shifts in the electron affinities were determined to be −0.003(4) meV for Pb(206)–Pb(208) and −0.002(4) meV for Pb(207)–Pb(208), providing insight to resolve previous discrepancies regarding the magnitude of these shifts.

Phys. Rev. A 106, L010801