Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Properties of negatively charged lithium ions and evaluation of the
  half-life of ${}^{7}$Be atom(s)   Bound state properties of the four-electron lithium ion Li$^{-}$ in its
ground $2^{2}S-$state and isotope-subsistuted ${}^{6}$Li$^{-}$ and
${}^{7}$Li$^{-}$ ions in their ground $2^1S-$state(s) are determined from the
results of accurate, variational computations. Another closely related problem
discussed in this study is accurate numerical evaluation of the half-life of
the beryllium-7 isotope. This problem is of paramount importance for modern
radiochemistry.

36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
30
The categories of this paper are: q-alg