Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhanced excitonic effects in the energy loss spectra of LiF and Ar at
  large momentum transfer   It is demonstrated that the bootstrap kernel [\onlinecite{sharma11}] for
finite values of ${\bf q}$ crucially depends upon the matrix character of the
kernel and gives results of the same good quality as in the ${\bf q}
\rightarrow 0$ limit. The bootstrap kernel is further used to study the
electron loss as well as absorption spectra for Si, LiF and Ar for various
values of ${\bf q}$. The results show that the excitonic effects in LiF and Ar
are enhanced for values of ${\bf q}$ away from the $\Gamma$-point. The reason
for this enhancement is the interaction between the exciton and high energy
inter-band electron-hole transitions. This fact is validated by calculating the
absorption spectra under the influence of an external electric field. The
electron energy loss spectra is shown to change dramatically as a function of
${\bf q}$.

18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex