Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Large second harmonic generation of LiCs2PO4 caused by the
  metal-cation-centered groups   We evaluated the individual atom contributions to the second harmonic
generation (SHG) coefficients of LiCs2PO4 (LCPO) by introducing the partial
response functionals on the basis of first principles calculations. The SHG
response of LCPO is dominated by the metal-cation-centered groups CsO6 and
LiO4, not by the nonmetal-cation-centered groups PO4 one expects from the
existing models and theories. The SHG coefficients of LCPO are determined
mainly by the occupied orbitals O-2p and Cs-5p as well as by the unoccupied
orbitals Cs-5d and Li-2p. For the SHG response of a material, the polarizable
atomic orbitals of the occupied and the unoccupied states are both important.

23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
1
The categories of this paper are: cs
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The categories of this paper are: eess
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th