Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Static-field ionization model of He-like ions for diagnostics of light
  field intensity   We study static-field ionization of He-like ions with nuclear charge number
in the range of $2\le Z \le 36$. Both the tunneling and over-the-barrier
regimes are considered. We calculate the ionization rates by three approximate
methods: a fitting formula based on the Perelemov-Popov-Terent'ev (PPT)
formula, a perturbative expansion in powers of $1/Z$, and a single-active
electron approximation, and compare them with reference ionization rates
computed by the multiconfiguration time-dependent Hartree-Fock (MCTDHF)
approach. The relative deviation of the rates computed by the PPT-based fitting
formula and the third-order perturbation theory from the rates computed by the
MCTDHF approach is found to be around 10\%. We discuss quantitatively the
contribution from the exchange interaction during the ionization by comparing
the single-active electron rates and the reference rates in which multielectron
effects are included. We find that a single-active electron approximation,
where the exchange interaction is neglected, results in the overestimation of
the ionization rates by 30\% for He and 2\% for He-like Kr, showing that the
magnitude of the effect of the exchange interaction scales approximately as
$1/Z$.

15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int