Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mesophase formation in a system of top-shaped hard molecules: Density
  functional theory and Monte Carlo simulation   We present the phase diagram of a system of mesogenic top-shaped molecules
based on the Parsons- Lee density functional theory and Monte Carlo simulation.
The molecules are modeled as a hard spherocylinder with a hard sphere embedded
in its center. The stability of five different phases is studied, namely,
isotropic, nematic, smectic A, smectic C, and columnar phases. The positionally
ordered phases are investigated only for the case of parallel alignment. It is
found that the central spherical unit destabilizes the nematic with respect to
the isotropic phase, while increasing the length of the cylinder has the
opposite effect. Also, the central hard sphere has a strong destabilizing
effect on the smectic A phase, due the inefficient packing of the molecules
into layers. For large hard sphere units the smectic A phase is completely
replaced by a smectic C structure. The columnar phase is first stabilized with
increasing diameter of the central unit, but for very large hard sphere units
it becomes less stable again. The density functional results are in good
agreement with the simulations.

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The categories of this paper are: supr-con
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
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The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: chem-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: econ
2
The categories of this paper are: math
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The categories of this paper are: adap-org