Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inelastic neutron scattering and lattice dynamical calculations in
  BaFe2As2   We report here first extensive measurements of the temperature dependence of
phonon density of states of BaFe2As2, the parent compound of the newly
discovered FeAs-based superconductors, using inelastic neutron scattering. The
experiments were carried out on the thermal time-of-flight neutron spectrometer
IN4 at the ILL on a polycrystalline sample. There is no appreciable change in
the spectra between T = 10 K and 200 K, although the sample undergoes a
magnetic as well as a tetragonal-to-orthorhombic structural phase transition at
140 K. This indicates a rather harmonic phonon system. Shell model lattice
dynamical calculations based on interatomic potentials are carried out to
characterize the phonon data. The calculations predict a shift of the
Ba-phonons to higher energies at 4 GPa. The average energy of the phonons of
the Ba-sublattice is also predicted to increase on partial substitution of Ba
by K to Ba0.6K0.4. The calculations show good agreement with the experimental
phonon spectra, and also with the specific heat data from the literature.

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The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph