Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Harmonics generation and intense terahertz radiation from polar
  molecules at multiphoton resonant excitation in laser fields   The coherent radiation spectrum of two-level polar molecules with UV
transition is studied at the multiphoton resonant excitation by a moderately
strong laser field. The spectrum corresponding to harmonic generation and
low-frequency radiation is investigated both analytically and numerically.
Specifically, a mechanism for generation of intense smoothly tunable terahertz
radiation by two-level molecular configurations (with dynamic Stark shifts)
possessing permanent dipole moments, is considered.

21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph