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RESEARCH PRODUCT

Isotope shifts and hyperfine structure in calcium 4snp and 4snf F Rydberg states

P. MüllerWilfried NörtershäuserKlaus WendtBruce A. Bushaw

subject

PhysicsIsotopePhotoionizationAtomic and Molecular Physics and OpticsIsotopes of calciumsymbols.namesakeIsotopic shiftKinetic isotope effectRydberg formulasymbolsPhysics::Atomic PhysicsRydberg stateAtomic physicsHyperfine structure

description

Isotope shifts and hyperfine structure have been measured in 4snp 1 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.

https://doi.org/10.1007/s100530070040