Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theoretical studies of the optical and EPR spectra for VO$^{2+}$ in
  Na$_{3}$C$_{6}$H$_{5}$O$_{7}\cdot 2$H$_{2}$O single crystal   On the basis of the perturbation formulas for a $d^{1}$ configuration ion in
a tetragonal crystal field, the three optical absorption bands and electron
paramagnetic resonance (EPR) parameters ($g$ factors $g_{i}$ and hyperfine
structure constants $A_{i}$ for $i = \|$ and $\perp$, respectively) of
VO$^{2+}$ in Na$_{3}$C$_{6}$H$_{5}$O$_{7}\cdot2$H$_{2}$O single crystals were
studied using the perturbation theory method. By simulating the calculated
optical and EPR spectra to the observed values, local structure parameters and
negative signs of the hyperfine structure constants $A_{i}$ of the octahedral
(VO$_{6}$)$^{8-}$ cluster in trisodium citrate dehydrate single crystal can be
obtained.

0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci