Eur. Phys. J. D 25, 113-121 (2003)
https://doi.org/10.1140/epjd/e2003-00096-6

The g_J-factor in the ground state of Ca⁺

¹ Johannes Gutenberg Universität, Institut für Physik, 55099 Mainz, Germany
² Institute of Atomic Physics and Spectroscopy, University of Latvia, Raina Blvd. 19, Riga, Latvia
³ Laboratoire Kastler Brossel, École Normal Supérieure et Université Pierre et Marie Curie, Case 74, 4 place Jussieu, 75005 Paris, France
⁴ 15 chemin du Billery, 38360 Sassenage, France

Corresponding authors: ^a werth@mail.uni-mainz.de - ^b paul.indelicato@spectro.jussieu.fr

Received: 9 December 2002
Revised: 24 February 2003
Published online: 29 April 2003

Abstract

We have determined the -factor of the ion in the electronic 4S_1/2 ground state on a cloud of ions confined in a Penning trap with a superimposed magnetic field of 1.43 T. We use a c.w. laser to prepare a Zeeman substate by optical pumping and induce transitions by a resonant microwave field at 40 GHz. Resonance is detected by a change in the fluorescence intensity originating from the ion cloud. We obtain a full width in the resonance of a few kHz and the fractional uncertainty of the line center, taking the average of several measurements, was . After calibrating the magnetic field by the cyclotron frequency of electrons stored in the same trap we obtain as result . The result is supported by a relativistic Multi-Configurational Dirac-Fock calculation.