Positions and Isotope Shifts of the H − ( 1 P 0 ) Dipole Resonances below the H ( n = 2 ) Threshold

The two lowest-lying members of the {sup 1}P{sup 0} dipole series of autodetaching resonances in H{sup {minus}} located just below the H(n=2) threshold have been observed and characterized, utilizing Doppler-tuned collinear laser spectroscopy. The resonance positions have been determined for both H{sup {minus}} and D{sup {minus}}, allowing the first critical test of the predicted isotope effects. The experimental isotope shifts are consistent with a small specific mass shift. We interpret these results as evidence for a rather small electron momentum correlation. {copyright} {ital 1997} {ital The American Physical Society}