[Wien] k-selectivity for RXES simulation ?

[Cormac McGuinness]

Dear Wien2k users

I would be interested in using Wien2k to simulate resonant x-ray emission
spectroscopy of a number of metal oxides. Specifically at the oxygen edge as
the O 1s soft x-ray emission spectrum gives the O 2p partial density of states.

Experimentally we typically record spectra with polarised incoming light aligned
along a specific crystal axis (O K-edge XAS), and the emission (O K-edge XES)
recorded propagating to the detector along another arbitrary axis, usually at
right angles. We can thus record soft x-ray emission spectra projected along
specific crystal axes (or pairs of axes).

Now, if we are near threshold then it is not uncommon that for lone conduction
bands that disperse slowly in a given direction from their minima as seen in
our spaghetti plot, we end up selecting (in the x-ray emission) ever increasing
sets of k-points that correspond to the k-points selected in the conduction band
states due to the excitation energy chosen.
This "k-selection" arises as the photon momentum is small, and thus the emission
occurs in a vertical line conserving k.
e.g. if the excitation is at the threshold for absorption and thus at the
conduction band minimum, say at the Gamma point, then the emission spectrum
only arises from the occupied states at the Gamma point.

Finally, my question(s) are as follows:

1) In order to simulate the RXES spectra near threshold is there a simple tool
to select by looking at specific energies within the conduction band a list of
k-points at that energy where there are states available ?

2) If I had such a list can I then just provide that to either tetra or qtl in
order to select the partial density of states (projected along specific axes)
arising ONLY from those selected k-points ?

Caveat: I am not a programmer! - but perhaps the tools are already in place ?


Yours

Cormac
--
Dr. Cormac McGuinness, Lecturer, School of Physics, Trinity College Dublin.
Phone: +353 1 8963547    Fax: +353 1 6711759    Office: SNIAM 3.17