Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Issue of Textured Crystallization of Ba(NO$_3$)$_2$ in Mesoporous
  SiO$_2$: Raman Spectroscopy and Lattice Dynamics Analysis   The lattice dynamics of preferentially aligned nanocrystals formed upon
drying of aqueous Ba(NO$_3$)$_2$ solutions in a mesoporous silica glass
traversed by tubular pores of approximately 12 nm are explored by Raman
scattering. To interpret the experiments on the confined nanocrystals polarized
Raman spectra of bulk single crystals and X-ray diffraction experiments are
also performed. Since a cubic symmetry is inherent to Ba(NO$_3$)$_2$, a special
Raman scattering geometry was utilized to separate the phonon modes of A$_g$
and E$_g$ species. Combining group-theory analysis and \textit{ab initio}
lattice dynamics calculations a full interpretation of all Raman lines of the
bulk single crystal is achieved. Apart from a small confinement-induced line
broadening, the peak positions and normalized peak intensities of the Raman
spectra of the nanoconfined and macroscopic crystals are identical.
Interestingly, the Raman scattering experiment indicates the existence of
comparatively large, $\sim$10-20 $\mu$m, single-crystalline regions of
Ba(NO$_3$)$_2$ embedded in the porous host, near three orders of magnitude
larger than the average size of single nanopores. This is contrast to the
initial assumption of non-interconnected pores. It rather indicates an
inter-pore propagation of the crystallization front, presumably via
microporosity in the pore walls.

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The categories of this paper are: astro-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: cs
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The categories of this paper are: alg-geom
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The categories of this paper are: math-ph
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The categories of this paper are: funct-an
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The categories of this paper are: stat
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The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex