Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The role of dipole-forbidden autoionizing resonances in non-resonant
  one-color two-photon single ionization of N$_2$   We present an experimental and theoretical energy- and angle-resolved study
on the photoionization dynamics of non-resonant one-color two-photon single
valence ionization of neutral N$_2$ molecules. Using 9.3 eV photons produced
via high harmonic generation and a 3-D momentum imaging spectrometer, we detect
the photoelectrons and ions produced from one-color two-photon ionization in
coincidence. Photoionization of N$_2$ populates the X $^2\Sigma^+_g$, A
$^2\Pi_u$, and B $^2\Sigma^+_u$ ionic states of N$_2^+$, where the
photoelectron angular distributions associated with the X $^2\Sigma^+_g$ and A
$^2\Pi_u$ states both vary with changes in photoelectron kinetic energy of only
a few hundred meV. We attribute the rapid evolution in the photoelectron
angular distributions to the excitation and decay of dipole-forbidden
autoionizing resonances that belong to series of different symmetries, all of
which are members of the Hopfield series, and compete with the direct
two-photon single ionization.

9
The categories of this paper are: nlin
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys