OBSERVATION OF THE PARTIAL DECAY INTO H0(N'=2) BY EXCITED H- NEAR THE N=3 AND 4 THRESHOLDS

Two resonances in the photodetachment spectrum of H-, one just below the n = 3 threshold and the other just below the n = 4 threshold, were observed decaying into H0(n' = 2) + e. The n = 3 resonance shows a preference for the n' = 2 channel when compared with total-detachment measurements. Fanoline-shape fits give central energies of 12.652 +/- 0.003 eV for H-**(3) and 13.338 +/- 0.004 eV for H-**(4). These values are in good agreement with current theoretical calculations.