https://doi.org/10.1007/s100530070040
Isotope shifts and hyperfine structure in calcium 4snp 1P1 and 4snf F Rydberg states
1
Institut für Physik, Johannes Gutenberg-Universität Mainz,
55099 Mainz, Germany
2
Pacific Northwest National Laboratory, Richland, WA 99352, USA
Received:
17
December
1999
Revised:
29
March
2000
Published online: 15 October 2000
Isotope shifts and hyperfine structure have been measured in 
P1 and 
Rydberg states for all stable calcium isotopes
and the radioisotope 41Ca using high-resolution laser spectroscopy.
Triple-resonance excitation via
Rydberg
state was followed by photoionization with a CO2 laser and mass
selective ion detection. Isotope shifts for the even-mass isotopes have been
analyzed to derive specific mass shift and field shift factors. The apparent
isotope shifts for 41Ca and 43Ca exhibit anomalous values that are
n-dependent. This is interpreted in terms of hyperfine-induced
fine-structure mixing, which becomes very pronounced when singlet-triplet
fine-structure splitting is comparable to the hyperfine interaction energy.
Measurements of fine-structure splittings for the predominant isotope
40Ca have been used as input parameters for theoretical calculation of the
perturbed hyperfine structure. Results obtained by diagonalizing the
second-order hyperfine interaction matrices agree very well with
experimentally observed spectra. These measurements allow the evaluation of
highly selective and sensitive methods for the detection of the rare 41Ca isotope.
PACS: 32.10.Fn – Fine and hyperfine structure / 32.80.Rm – Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
