Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Packing Concave Molecules in Crystals and Amorphous Solids: On the
  Connection between Shape and Local Structure   The structure of the densest crystal packings is determined for a variety of
concave shapes in 2D constructed by the overlap of two or three disks. The
maximum contact number per particle pair is defined and proposed as a useful
means of categorizing particle shape. We demonstrate that the densest packed
crystal exhibits a maximum in the number of contacts per particle but does not
necessarily include particle pairs with the maximum contact number. In
contrast, amorphous structures, generated by energy minimization of high
temperature liquids, typically do include maximum contact pairs. The amorphous
structures exhibit a large number of contacts per particle corresponding to
over-constrained structures. Possible consequences of this over-constraint are
discussed.

26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin