Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pair correlation functions in nematics, free-energy functional and
  isotropic-nematic transition   We develop a free energy functional for an inhomogeneous system that contains
both symmetry conserved and symmetry broken parts of the direct pair
correlation function. These correlation functions are found by solving the
Ornstein- Zernike equation with the Percus-Yevick closure relation. The method
developed here gives the pair correlation functions in the ordered phase with
features that agree well with the results found by computer simulations. The
theory predicts accurately the isotropic-nematic transition in a system of
anisotropic molecules and can easily be extended to study other ordered phases
such as smectics and crystalline solids.

18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol