Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultrafast Processes in Isomeric Pyrene-N-methylacetamides: Formation of
  Hydrogen Bond Induced Static Excimers with Varied Coupling Strength   Pyrene based molecules are inclined to form excimers through self-association
upon photoexcitation. In this work, the pyrene core is functionalized with
N-methylacetamide group at the position 1 or 2, to develop
pyren-1-methylacetamide (PyMA1) and pyren-2-methylacetamide (PyMA2),
respectively. Upon photoexcitation, PyMA1 and PyMA2, at 1.0mM, in toluene, have
formed predominantly static excimers. The steady state spectroscopic studies
have showed that the excitonic coupling of PyMA1 dimers are much stronger in
solution than its isomeric counterpart, PyMA2. The transient absorption (TA)
measurements over fs-ps regime (fs-TA) showed that the formation of static
excimers with the strongly-coupled pre-associated dimers, in PyMA1, happens in
approx. 560fs, whereas, the excimers for the weakly-coupled pre-associated
dimers in PyMA2 have formed in much slower time scale (approx. 65ps). The
introduction of methylacetamide group at the position 1 or 2 on pyrene ring,
was believed to have allowed forming hydrogen bonded excimers with different
degrees of excitonic coupling.

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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: cs