Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optoelectronic Properties of Carbon Nanorings: Excitonic Effects from
  Time-Dependent Density Functional Theory   The electronic structure and size-scaling of optoelectronic properties in
cycloparaphenylene carbon nanorings are investigated using time-dependent
density functional theory (TDDFT). The TDDFT calculations on these molecular
nanostructures indicate that the lowest excitation energy surprisingly becomes
larger as the carbon nanoring size is increased, in contradiction with typical
quantum confinement effects. In order to understand their unusual electronic
properties, I performed an extensive investigation of excitonic effects by
analyzing electron-hole transition density matrices and exciton binding
energies as a function of size in these nanoring systems. The transition
density matrices allow a global view of electronic coherence during an
electronic excitation, and the exciton binding energies give a quantitative
measure of electron-hole interaction energies in the nanorings. Based on
overall trends in exciton binding energies and their spatial delocalization, I
find that excitonic effects play a vital role in understanding the unique
photoinduced dynamics in these carbon nanoring systems.

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The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
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The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat