Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Study of structure and lattice dynamics of the Sr$_2$CuO$_2$Cl$_2$(001)
  surface by helium-atom scattering
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics