Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measuring the intrinsic charge transfer gap using K-edge X-ray
  absorption spectroscopy   Pre-edge features in X-ray absorption spectroscopy contain key information
about the lowest excited states and thus on the most interesting physical
properties of the system. In transition metal oxides they are particularly
structured but extracting physical parameters by comparison with a calculation
is not easy due to several computational challenges. By combining core-hole
attraction and correlation effects in first principles approach, we calculate
Ni K-edge X-ray absorption spectra in NiO. We obtain a striking, parameter-free
agreement with experimental data and show that dipolar pre-edge features above
the correlation gap are due to non-local excitations largely unaffected by the
core-hole. We show that in charge transfer insulators, this property can be
used to measure the correlation gap and probe the intrinsic position of the
upper-Hubbard band.

31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an