Using mass spectrometry we have confirmed that Sr2+ ions are produced from laser-populated Rydberg states by the associative ionization process Sr(5snl) + Sr(5s2) → Sr2+ + e-. Dimer ion signal was detected for the 5s6d3D2 level, indicating that the binding energy of Sr2+ exceeds 0.77 eV. We have observed that under certain conditions the Rydberg states are destroyed by electron-impact ionization before an associative ionization collision can occur.
© 1978 Optical Society of America
E. F. Worden, J. A. Paisner, and J. G. Conway, "Associative ionization of laser-excited Rydberg states in strontium vapor," Opt. Lett. 3, 156-158 (1978)