Study of spectra of even-parity highly excited states of Sm atom

Spectra of even-parity highly excited states of the Sm atom have been systematically studied with two color three-step excitation and photoionization detection method. With two different excitation paths, the atom is resonantly excited to the given bound states where it is detected by photoionization. The wavelength of the first laser is fixed at 627.50 nm 01 624.41 nm so that the Sm atom can be excited to the two different intermediate states with the 4f(6)6s6p configuration. Then the wavelength of the second laser is scanned from 440 to 700 nm to further excite the atom, so that the highly excited states in the 30040-38065 cm(-1) energy range can be populated. Based on the accurate calibration of wavelength and the selection rule, the level energies of 136 even-parity states and their relative line intensities are determined with a unique assignment of the momentum. Except for the level energies of 71 even-parity states that are confirmed by the present work, all information provided in this work has not been reported previously.