Stable Bound States of Yb and Pr Negative Ions

S. P. Andreev, Vladimir A. Polunin

Kathrin Sebald, S. Kück, ERNST HEUMANN +4 more

E. V. Vidolova-Angelova, Л. Н. Иванов, E. P. Ivanova +1 more

H. H. Andersen, T. Andersen, U. V. Pedersen

The previously reported observation of stable negative Yb ions has been reinvestigated. No evidence is found for the existence of such ions or for long-lived metastable ions. This conclusion is limited to Yb ions with binding energies larger than 3 meV.

R.A. Pople, C. D. Finch, F. B. Dunning

Yong Li, C. D. Lin

We examine the existence of stable bound states of some diatomic molecular ions where the neutral molecule itself is either unbound or barely bound. Two bound states have been found for the ${\mathrm{HeH}}^{\ensuremath{-}}$ ion even though HeH is known to be unbound. We have found no bound states for ${\mathrm{He}}_{2}^{\ensuremath{-}}$ even though ${}^{4}{\mathrm{He}}_{2}$ is known to have one bound state. The predicted binding energies for ${\mathrm{HeH}}^{\ensuremath{-}}$ are of the order of 1 K and depend sensitively on the isotope combinations. Other weakly bound negative ions such as ${\mathrm{NeH}}^{\ensuremath{-}}$ and ${\mathrm{ArH}}^{\ensuremath{-}}$ have also been investigated. These weakly bound molecular ions are good candidates for cold collision experiments.