Unexpectedly large difference of the electron density at the nucleus in the 4p2P1/2,3/2 fine-structure doublet of Ca +

authored by
Chunyan Shi, Florian Gebert, Christian Gorges, Simon Kaufmann, Wilfried Nörtershäuser, Bijaya Kumar Sahoo, A. Surzhykov, Vladimir A. Yerokhin, Julian C. Berengut, Fabian Wolf, J. C. Heip, Piet Oliver Schmidt

We measured the isotope shift in the 2S 1 / 22P 3 / 2 (D2) transition in singly ionized calcium ions using photon recoil spectroscopy. The high accuracy of the technique enables us to compare the difference between the isotope shifts of this transition to the previously measured isotopic shifts of the 2S 1 / 22P 1 / 2 (D1) line. This so-called splitting isotope shift is extracted and exhibits a clear signature of field shift contributions. From the data, we were able to extract the small difference of the field shift coefficient and mass shifts between the two transitions with high accuracy. This J-dependence is of relativistic origin and can be used to benchmark atomic structure calculations. As a first step, we use several ab initio atomic structure calculation methods to provide more accurate values for the field shift constants and their ratio. Remarkably, the high-accuracy value for the ratio of the field shift constants extracted from the experimental data is larger than all available theoretical predictions.

Institute of Quantum Optics
CRC 1227 Designed Quantum States of Matter (DQ-mat)
External Organisation(s)
National Metrology Institute of Germany (PTB)
Technische Universität Darmstadt
Physical Research Laboratory India
Technische Universität Braunschweig
St. Petersburg State Polytechnical University
University of New South Wales (UNSW)
Applied Physics B: Lasers and Optics
Publication date
Publication status
Peer reviewed
ASJC Scopus subject areas
Physics and Astronomy (miscellaneous), Physics and Astronomy(all)
Electronic version(s)
https://doi.org/10.1007/s00340-016-6572-z (Access: Unknown)