Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The spectroscopic parameters of sodium cyanide, NaCN (X 1A'), revisited   The study of the rotational spectrum of NaCN (X $^1$A') has recently been
extended in frequency and in quantum numbers. Difficulties have been
encountered in fitting the transition frequencies within experimental
uncertainties. Various trial fits traced the difficulties to the incomplete
diagonalization of the Hamiltonian. Employing fewer spectroscopic parameters
than before, the transition frequencies could be reproduced within experimental
uncertainties on average. Predictions of $a$-type $R$-branch transitions with
$K_a \le 7$ up to 570 GHz should be reliable to better than 1 MHz. In addition,
modified spectroscopic parameters have been derived for the 13C isotopic
species of NaCN.

27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn