Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A systematic approach to determine the spectral characteristics of
  molecular magnets   We devise a formalism to investigate in a systematic way the spectroscopic
magnetic excitations in molecular magnets. This consists in introducing a
bilinear spin Hamiltonian that allows for discrete coupling parameters
accounting for distinct spin coupling mechanisms among the constituent magnetic
ions, as well as the influence of the nonmagnetic ions in the system. The model
is applied to explore the magnetic excitations of the trimeric magnetic
compounds $\mathrm{A_3Cu_3(PO_4)_4}$ $\mathrm{(A\ =\ Ca,\ Sr,\ Pb)}$ and the
tetrameric molecular magnet $\mathrm{Ni_4Mo_{12}}$. Our results are in a very
good agreement with the available experimental data: For all trimers
$\mathrm{A_3Cu_3(PO_4)_4}$, calculations reveal the existence of one thin
energy band referring to the flatness of observed excitation peaks. Moreover
for the tetramer $\mathrm{Ni_4Mo_{12}}$, we concluded that the magnetic
excitations may be traced back to the specific geometry and complex chemical
structure of the exchange bridges leading to the splitting and broadness of the
peaks centered about 0.5 meV and 1.7 meV.

5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex