[Wien] Questions regarding xspec and optic

[Zhu, Jianxin]

Hi,

For X-ray ABS spectra (that explained in 8.10), I don't believe we need to create a linear grid throughout the whole BZ.  As for with or without core hole, it is a physical issue not a technical issue.

In the chapter 8.16 of UG, it is indeed written


In order to calculate XMCD and x-ray absorption spectra, eigenvalues must be evaluated over a

mesh in the whole Brillouin zone;

I'm not sure this requirement is really needed for X-ray spectra.


For your question 1,  you can always break the multiplicity by treating the atom with core-hole to be different an atom type from the rest.

I'm interested in seeing followup discussions by others.

Cheers,

Jianxin


From: prasenjit roy <prasenjit1988 at gmail.com<mailto:prasenjit1988 at gmail.com>>
Reply-To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at<mailto:wien at zeus.theochem.tuwien.ac.at>>
Date: Mon, 11 Feb 2013 16:45:04 +0100
To: <wien at zeus.theochem.tuwien.ac.at<mailto:wien at zeus.theochem.tuwien.ac.at>>
Subject: [Wien] Questions regarding xspec and optic

Dear WIEN2k users and Prof. Blaha,


                 I am using WIEN11.1 version. While doing the XANES and XMCD calculations I faced few problems, which I have arranged below. I searched the mailing list, and also the Exercise11.pdf<http://www.wien2k.at/reg_user/textbooks/WIEN2k_lecture-notes_2011/Exercises_11.pdf> but did not find the appropriate solution. My System is Fe2P, S.grp - 189. Metallic. Unitcell contains 6 Fe (Fe1: 3g, Fe2: 3f site) and 3 P(P1: 2c, P2:1b).

              1. For XANES: If my structure file contains atoms with multicplicity > 1 (in my case, 3), then after making the supercell (1x1x2), if I remove one 1s electron from Fe1, it actually creating 3 core-holes instead of 1 (inside the supercell). So How should I create the case.struct file at the first place?

              2. For obtaining XANES without core-hole, { and also with core-hole } do I need to create k-points over the whole BZ ( in chapter 8.16 of UG (pp 156), it is written that for X-ray ABS spectra, eigenvalue must be calculated over whole BZ )?

              3. Is the Energy window in case.inxs depends on EMAX, NBANDS in case.in1c?

              4. For XMCD, I need only K-edge . Even for that should I do SO calculation? If yes, as far as I understood, the lineup of steps will look like this after creating the unit-cell,:: a) Init_lapw ; b) Initso_lapw (or, symmetso -c ?); c) runsp_lapw -so ; d) x kgen -so ; e) put FERMI in case.in2c ; f) runsp_lapw -so -c -s lapw1 -e lcore ; g) x opticc -so -up ; h) x joint -up ; i) x kram -up .
                 For more accurate calculation, should I use core-hole approach for XMCD, as suggested here<http://www.wien2k.at/reg_user/textbooks/WIEN2k_lecture-notes_2011/Ambrosch-Draxl_optics_bse.pdf>?

                Thank you very much In Advance.


With Regards,
Prasenjit Roy
Radboud University
Nijmegen
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