The electron affinity of tungsten

The electron affinity of tungsten has been measured using laser photodetachment threshold spectroscopy in a collinear geometry. The electron affinity was determined to 6583.6(6) cm^-1 by observing the onset of the process when W^- ions in the 5d⁵6s²5d^56s^2 ⁶S_5/2 ground state are photodetached producing neutral W atoms in the 5d⁴6s²5d^46s^2 ⁵D₀ ground state. The measured value is in agreement with previous measurements and improves the accuracy by almost two orders of magnitude. Further, a photodetachment signal below the ground state photodetachment threshold was found, which indicates the existence of a bound excited state in W^-.