Threshold photodetachment of H-

The electron affinities of atomic hydrogen and deuterium are determined by tunable-laser threshold-photodetachment spectroscopy: the electron affinities of H (F = 0) and D (F = 1/2) are 6082.99 + or - 0.15 and 6086.2 + or - 0.6/cm, respectively. The value for H is a 20-fold improvement over previous experimental determinations.