High efficiency laser resonance ionization of plutonium.

Three-step resonance photoionization spectra of plutonium have been studied with Ti:Sapphire lasers for the development of efficient laser ionization schemes for ultra-trace analysis of Pu isotopes by resonance ionization mass spectrometry. We observed eighteen intermediate excited states of even parity in the energy range 35568-36701 [Formula: see text], thirteen of them have not been previously documented, and a larger number of high-lying excited states and autoionizing states of odd-parity between 48238 and 49510 [Formula: see text]. Three-color, three-photon ionization schemes via six intermediate states were evaluated under similar ion source operating conditions.