  For any finite link $L$ in $\mathbb{R}^3$ we prove the existence of a
high-energy complex-valued eigenfunction of the hydrogen atom such that its
nodal set contains a union of connected components diffeomorphic to $L$. This
problem goes back to Berry, who constructed such eigenfunctions in the case
where $L$ is the trefoil knot or the Hopf link and asked the question about the
general result.
