Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Symmetries of Nonlinear Vibrations in Tetrahedral Molecular
  Configurations   We study nonlinear vibrational modes of oscillations for tetrahedral
configurations of particles. In the case of tetraphosphorus, the interaction of
atoms is given by bond stretching and van der Waals forces. Using equivariant
gradient degree, we present a full topological classification of the
spatio-temporal symmetries of the periodic solutions. This procedure gives all
the symmetries of the nonlinear vibrations for general force fields.

31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol