Observation of the partial decay into H sup 0 ( n prime =2) by excited H sup minus near the n =3 and 4 thresholds

Two resonances in the photodetachment spectrum of H{sup {minus}}, one just below the {ital n}=3 threshold and the other just below the {ital n}=4 threshold, were observed decaying into H{sup 0}({ital n}{prime}=2)+{ital e}. The {ital n}=3 resonance shows a preference for the {ital n}{prime}=2 channel when compared with total-detachment measurements. Fano-line-shape fits give central energies of 12.652{plus minus}0.003 eV for H{sup {minus}**}(3) and 13.338{plus minus}0.004 eV for H{sup {minus}**}(4). These values are in good agreement with current theoretical calculations.