Abstract

A four-even-parity series belonging to transitions from the $5s\prime {\left[1/2\right]}_1^0$ level to the $\left({}^2{p}_{3/2}^0\right)$ np, nf levels of krypton have been observed, we believe for the first time, using a resonant multistep two-color photoionization method¹ including a VUV photon for the first step and no time delay between the two beams. The energies of 7p′[3/2]₁, 7p′[1/2]₁, 7p′[3/2]_2, 7p′[l/2]₀, np[l/2]₁, np[3/2]₂, np[l/2]₀, and nf[3/2]_1,2 levels are determined, and the principal quantum number n is assigned up to 45, 32, 49, and 44, respectively. Strong irregularities occur due to the mixing of the np series with 7p′ levels. A detailed study is performed for the 5s′[l/2]₁ →np[l/2]₀ series, which is the most intense, using Lu-Fano diagrams and MQDT² analysis. In the spectral range around 112,700 cm⁻¹, the np[l/2]₀ members reach up to 90% of the p′ character. Up to now most of the work on the rare gas even-parity Rydberg series was based on nonselective formation of metastable States for the first step, mainly from low density post discharges.

© 1990 Optical Society of America