LASER SPECTROSCOPY OF THE BE- ION - BINDING-ENERGIES OF METASTABLE STATES

By using a combination of laser photodetachment and resonant ionizatio n spectroscopy, the binding energy of the 1s(2)2s2p(2) (4)p State in B e- is determined with much improved accuracy to be 290.99+/-0.10 meV. This value is considerably larger than the recent measurement of 261+/ -10 meV, but only slightly above the new theoretical value of 289.1 +/ - 1.0 meV. The transition wavelength of 1s(2)2s2p(2) P-4(3/2-1s22p3 4S 3/2) is determined by laser excitation to be at 2653.18+/-0.08 Angstro m, yielding the binding energy of the 1s(2)2p(3) S-4 State in Be- to b e 295.49+/-0.25 meV, in good agreement with the newest theoretical res ult of 295.0+/-0.7 meV.