Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Ultra-broad near-infrared photoluminescence from crystalline
  (K-crypt)2Bi2 containing [Bi2]2- dimers
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th