Observation of autoionizing states of beryllium by resonance ionization mass spectrometry

We have made the first observations of the Be 2p21S state, and of high-lying members of the Rydberg series 2pnd 1P0 (n less than or equal to 16), by resonance ionization mass spectrometry (RIMS). The energy of the 1S state agrees well with theoretical predictions, if corrections are made for intershell electron correlations. These results show that precision specroscopy can be performed by RIMS with samples of a few hundred atoms, and that direct multiphoton excitation of autoionizing states may be a useful new addition to the existing catalogue of resonance ionization schemes