Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On highly accurate calculations of the excited $n^1S(L = 0)-$states in
  helium atoms   The total energies and various bound state properties of the excited $2^1S(L
= 0)-$states in two-electron helium atoms, including the ${}^{\infty}$He,
${}^4$He and ${}^3$He atoms, are determined to very high numerical accuracy.
The convergence of the results obtained for some electron-nuclear and
electron-electron expectation values and, in particular, for the
electron-nuclear and electron-electron cusp values, is discussed. The field
component of the isotope shift and lowest order QED correction are estimated
for the $2^1S(L = 0)-$states in the ${}^4$He and ${}^3$He atoms. We also apply
our highly accurate methods to numerical computations of the excited
$n^1S-$states (for $n$ = 3 and 4) in two-electron atomic systems.

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The categories of this paper are: math-ph
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an