Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Conical Intersections and Charge Localization in a Minimal Model of a
  Monomethine Dye System: Degenerate Case   We investigate a minimal valence-bond-based model Hamiltonian for
photoisomerization of monomethine dyes. These include a broad class of large
conjugated organic molecules including diarylmethane and cyanine dyes, and the
chromophores of fluorescent proteins. The model fulfills the most basic
expectations for a double bond photoisomerization model: 1) it describes
favorable twisting in the excited state and 2) it describes conical
intersections which can mediate radidationless decay. We examine the topology,
topography and extent of the conical intersection seams. Important properties
of the model include 1) two regimes of the coupling ratio where the first
excited state intersects the ground and a higher excited state along orthogonal
twisting coordinates or along the same coordinate 2) first and higher excited
state intersections occurring in regions of little or no twisting and 3) charge
localization connected with excited-state twisting which changes
discontinuously across a conical intersection. The model is promising as a
simple extension of empirical force fields in order to describe
photoisomerization processes in methine-bridged systems and as a starting point
for more elaborate models which may include antisymmetric internal couplings or
which may be interfaced with environmental or quantum dynamical models.

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The categories of this paper are: q-bio
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The categories of this paper are: atom-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: supr-con
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The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
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The categories of this paper are: math
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The categories of this paper are: nlin
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys