Observation of Highly Excited Hydrogenlike States of Ca + Sr + , Ba + , and Mg + Ions

Petr A. Bokhan

David J. Wineland, Wayne M. Itano

F. M. Kelly, M. S. Mathur

The Hanle effect in the singlet states of Sr, Ba, Mg, and Ca has been studied over a range of densities. The low density observations lead to an accurate lifetime measurement of the singlet excited levels, and calculation of the related oscillator strengths. The depolarization cross sections, [Formula: see text], for collision with ground level neutral atoms have been obtained from the high density data.

David W. Fahey, W. F. Parks, L. D. Schearer

A thermal beam of helium (2 3 S 1 ) metastable atoms was used to excite coherently the 2 P 3/2 levels of Ca, Sr and Ba in a Penning ionising collision. The coherent excitation of the ions appears as a linear polarisation of the optical emission from the excited ions. The degree of linear polarisation is 5.5, 3.5 and 0.5% for Ca, Sr and Ba, respectively, with the polarisation parallel to the beam direction. Hanle effect signals from the 2 P 3/2 level of Sr were observed and the radioactive decay rate measured.

Jeffrey L. Krause, R. Stephen Berry

Conditional probability distributions for the valence electrons of alkaline-earth atoms in their ground and valence excited states are constructed using large-basis Sturmlan configuration-interaction wave functions for two electrons in frozen, effective-core potentials. The distributions indicate that the ground states of Be, Mg, Ca, Sr, and Ba, and the valence excited states of Be, are much more like linear triatomic molecules, akin to doubly excited He, than like independent-particle systems such as the ground states of He and He-like ions.

Y. K. Ho, Yan Zhao