Hyperfine structure of odd-parity levels in91Zr I

Hyperfine structures have been investigated for odd-parity 4d 2 5s5p and 4d 3 5p levels for six 91 Zr I transitions in the spectral range 458-549 nm using Doppler-free saturated absorption spectroscopy in a sputtered vapour. The measured hyperfine structure constants, A and B , together with results of previous studies were analysed by means of a parametric method. The interpretation was based on refined multiconfigurational fine structure calculations, which include the main Rydberg series configuration states. The analysis suggests a drastic revision of the composition of the 4d5s 2 5p configuration levels. The main one-electron hyperfine structure parameters for the lowest configuration, i.e. 4d 2 5s5p, are determined to be a 5s 10 = -2672(61) MHz, a 4d 01 = -115.8(3.4) MHz, a 5p 01 = -127.4(3.7) MHz, b 4d 02 = -93.5(2.8) MHz and b 5p 02 = -139.9(5.1) MHz. These values are in excellent agreement with ab initio calculations, justifying our choice of the perturbing configuration states.