Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum-State-Sensitive Detection of Alkali Dimers on Helium
  Nanodroplets by Laser-Induced Coulomb Explosion   Rubidium dimers residing on the surface of He nanodroplets are doubly ionized
by an intense fs laser pulse leading to fragmentation into a pair of
$\mathrm{Rb^+}$ ions. We show that the kinetic energy of the $\mathrm{Rb^+}$
fragment ions can be used to identify dimers formed in either the X
$^1\Sigma_{\mathrm{g}}^+$ ground state or in the lowest-lying triplet state, a
$^3\Sigma_{\mathrm{u}}^+$. From the experiment, we estimate the abundance ratio
of dimers in the a and X states as a function of the mean droplet size and find
values between 4:1 and 5:1. Our technique applies generally to dimers and
trimers of alkali atoms, here also demonstrated for $\mathrm{Li_2}$,
$\mathrm{Na_2}$, and $\mathrm{K_2}$, and will enable fs time-resolved
measurements of their rotational and vibrational dynamics, possibly with atomic
structural resolution.

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The categories of this paper are: dg-ga
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
1
The categories of this paper are: cs
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The categories of this paper are: alg-geom
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The categories of this paper are: supr-con
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The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: quant-ph