High-resolution vacuum-ultraviolet and ultraviolet photoionization spectroscopy of krypton

Accurate spectroscopy of krypton is performed on five transitions from the (4p(6)) (1)S(0) ground state to the 5d[1/2](1), 6s[3/2](1), 5p[1/2](0), 5p[3/2](2) and 5p[5/2](2) excited states (jl-coupling notation) by means of 1VUV + 1UV and 2UV + 1UV resonance-enhanced photoionization. Isotope shifts of all six stable isotopes are determined, and a King plot analysis indicates a large field shift factor even for transitions in which no s electron is involved. Absolute frequency calibration is performed on three transitions, leading to a novel determination of the excited state energies of Kr with an accuracy of similar to0.0013 cm(-1). An accurate value for the ionization energy of (86)Kr, 112 914.516(14) cm(-1), is derived along with ionization energies for all even isotopes. The ac Stark effect on the two-photon transition to the 5p[1/2](0) excited state is investigated. For light intensities up to similar to260 MW cm(-2) a linear shift of 0.75(48) Hz (W cm(-2))(-1) is observed, while at higher intensities the line exhibits a sub-linear shift and an asymmetric broadening. Consequences of the results obtained for the 5p[1/2]0 state on resonance-enhanced narrow-band XUV/VUV generation are discussed.