The effect of field strength on the resonance structure of three-photon ionization spectra of the samarium atom

Amplitude ratios of resonance maxima caused by two-photon transitions from different levels of the ground term of the samarium atom are studied experimentally and theoretically as functions of the laser-radiation field strength. The results of these studies are shown to be promising for identifying the resonance structure of three-photon ionization spectra of the samarium atom. A not yet observed excited even-parity state with energy E ≈ 36789.1 cm −1 and hypothetical values of total angular momentum J = 5, 6 has been discovered.