Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radiative cooling functions for primordial molecules   Cooling of primordial gas plays a crucial role in the birth of the first
structures in our Universe. Due to the low fractional abundance of molecular
species at high redshifts, spontaneous emission rather than collisions
represents the most efficient way to cool the pristine plasma. In the present
work, radiative cooling functions are evaluated for the diatomic species HD,
HD$^+$, HeH$^+$, LiH and LiH$^+$. Cooling functions for the triatomic ions
H$_3^+$ and H$_2$D$^+$ are also considered. Analytic fits as functions of
temperature are provided.

13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg