%0 Journal Article
%T Stable He$^-$ can exist in a strong magnetic field
%A A. V. Turbiner
%A J. C. Lopez Vieyra
%J Physics
%D 2013
%I arXiv
%R 10.1103/PhysRevLett.111.163003
%X The existence of bound states of the system $(\al,e,e,e)$ in a magnetic field $B$ is studied using the variational method. It is shown that for $B \gtrsim 0.13\,{\rm a.u.}$ this system gets bound with total energy below the one of the $(\al,e,e)$ system. It manifests the existence of the stable He$^-$ atomic ion. Its ground state is a spin-doublet $^2(-1)^{+}$ at $0.74\, {\rm a.u.} \gtrsim B \gtrsim 0.13\, {\rm a.u.}$ and it becomes a spin-quartet $^4(-3)^{+}$ for larger magnetic fields. For $0.8\, {\rm a.u.} \gtrsim B \gtrsim 0.7\, {\rm a.u.}$ the He$^-$ ion has two (stable) bound states $^2(-1)^{+}$ and $^4(-3)^{+}$.
%U http://arxiv.org/abs/1307.4810v2