Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cold collisions of OH and Rb. I: the free collision   We have calculated elastic and state-resolved inelastic cross sections for
cold and ultracold collisions in the Rb($^1 S$) + OH($^2 \Pi_{3/2}$) system,
including fine-structure and hyperfine effects. We have developed a new set of
five potential energy surfaces for Rb-OH($^2 \Pi$) from high-level {\em ab
initio} electronic structure calculations, which exhibit conical intersections
between covalent and ion-pair states. The surfaces are transformed to a
quasidiabatic representation. The collision problem is expanded in a set of
channels suitable for handling the system in the presence of electric and/or
magnetic fields, although we consider the zero-field limit in this work.
Because of the large number of scattering channels involved, we propose and
make use of suitable approximations. To account for the hyperfine structure of
both collision partners in the short-range region we develop a
frame-transformation procedure which includes most of the hyperfine
Hamiltonian. Scattering cross sections on the order of $10^{-13}$ cm$^2$ are
predicted for temperatures typical of Stark decelerators. We also conclude that
spin orientation of the partners is completely disrupted during the collision.
Implications for both sympathetic cooling of OH molecules in an environment of
ultracold Rb atoms and experimental observability of the collisions are
discussed.

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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg