Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Origin of C$_{60}$ surface reconstruction resolved by atomic force
  microscopy   Surface adsorption of C$_{60}$ affects its chemical and electronic
properties. Numerous studies have reported observation of bright and dark
fullerenes on metal surfaces that suggest extensive surface reconstruction,
however, the underpinning mechanism of the reconstruction remains under debate.
Here we report tip-functionalised non-contact atomic force microscope (ncAFM)
measurements which unambiguously reveal that C$_{60}$ fullerenes adsorb with
three well-defined adsorption heights on the Cu(111) surface, consistent with
theoretical reports of top-layer hollow site, single-atom vacancies, and
surface nanopits. Using single molecule resolution $\Delta f(z)$ measurements
we identify well defined adsorption heights specific to each site, confirming
the presence of a complex vacancy model for C$_{60}$ monolayers on metal
surfaces.

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The categories of this paper are: ao-sci
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: cs
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The categories of this paper are: solv-int
2
The categories of this paper are: math
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
17
The categories of this paper are: q-fin
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The categories of this paper are: q-alg
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol