Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Neutron scattering study of the vibrations in vitreous silica and
  germania   The incoherent approximation for the determination of the vibrational density
of states of glasses from inelastic neutron or x-ray scattering data is
extended to treat the coherent scattering. The method is applied to new room
temperature measurements of vitreous silica and germania on the thermal
time-of-flight spectrometer IN4 at the High Flux Reactor in Grenoble. The
inelastic dynamic structure factor at the boson peak turns out to be reasonably
well described in terms of a mixture of rotation and translation of practically
undistorted SiO4 or GeO4 tetrahedra. The translational component exceeds the
expectation of the Debye model by a factor of two. A possible relation of this
excess to the phonon shift and broadening observed in x-ray Brillouin
scattering experiments is discussed.

8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol