Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electronic Excitations from a Perturbative LDA+GdW Approach   We discuss an efficient approach to excited electronic states within
ab-initio many-body perturbation theory (MBPT). Quasiparticle corrections to
density-functional theory result from the difference between metallic and
non-metallic dielectric screening. They are evaluated as a small perturbation
to the DFT-LDA band structure, rather than fully calculating the self energy
and evaluating its difference from the exchange-correlation potential. The
dielectric screening is desribed by a model, which applies to bulk crystals, as
well as, to systems of reduced dimension, like molecules, surfaces, interfaces,
and more. The approach also describes electron-hole interaction. The resulting
electronic and optical spectra are slightly less accurate but much faster to
calculate than a full MBPT calculation. We discuss results for bulk silicon and
argon, for the Si(111)-(2x1) surface, the SiH4 molecule, an argon-aluminum
interface, and liquid argon.

27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an