Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Orientation and Motion of Water Molecules at Air/Water Interface   Analysis of SFG vibrational spectra of OH stretching bands in four
experimental configurations shows that orientational motion of water molecule
at air/water interface is libratory within a limited angular range. This
picture is significantly different from the previous conclusion that the
interfacial water molecule orientation varies over a broad range within the
vibrational relaxation time, the only direct experimental evidence for
ultrafast and broad orientational motion of a liquid interface by Wei et al.
[Phys. Rev. Lett. 86, 4799, (2001)] using single SFG experimental
configuration.

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The categories of this paper are: nucl-th
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The categories of this paper are: hep-th
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The categories of this paper are: stat
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: econ
8
The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex