Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theoretical spectroscopy techniques applied to graphene EELS and optics   A thorough understanding of the electronic structure is a necessary first
step for the design of nanoelectronics, chemical/bio-sensors, electrocatalysts,
and nanoplasmonics using graphene. As such, theoretical spectroscopic
techniques to describe both direct optical excitations and collective
excitations of graphene are of fundamental importance. Starting from density
functional theory (DFT) we use the time dependent linear response within the
random phase approximation (TDDFT-RPA) to describe the loss function
-Im{{\epsilon}\overline{ }^{1}(q,{\omega})} for graphene. To ensure any
spurious interactions between layers are neglected, we employ both a radial
cutoff of the Coulomb kernel, and extra vacuum directly at the TDDFT-RPA level.

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The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
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The categories of this paper are: eess
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The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
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The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
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The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
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The categories of this paper are: solv-int