rlu to a.u. conversion

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sitangshu
Posts: 175
Joined: Thu Jan 05, 2017 8:08 am

rlu to a.u. conversion

Post by sitangshu » Wed Nov 16, 2022 7:37 am

Dear all,

I have one fundamental query: what is the conversion factor between rlu (crystal or fractional or rdeuced) and a.u. (atomic units) used in yambo?
I have an exciton dispersion using interpolation whose reciprocal coordinates looks like this. My query is how 0.20778585E-01 is calculated?
|q| (a.u.) q_x (rlu) q_y (rlu) q_z (rlu)
0.20778585E-01 0.17241379E-01 -0.17347235E-17 0.0000000
The non-interpolated exciton energies do not show |q| (a.u.), which is required to compare with interpolated ones.
Is |q| (a.u.) = sqrt (q_x^2 +q_y^2 +q_z^2) / (2*pi/a0), where a0 = lattice constant in scf.

I am using Version 5.1.0 Revision 21422 Hash (prev commit) fde6e2a07
Many thanks for your response.

Regards,
Sitangshu Bhattacharya
Indian Institute of Information Technology-Allahabad
India
Web-page: http://profile.iiita.ac.in/sitangshu/
Institute: http://www.iiita.ac.in/

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Daniele Varsano
Posts: 3773
Joined: Tue Mar 17, 2009 2:23 pm
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Re: rlu to a.u. conversion

Post by Daniele Varsano » Wed Nov 16, 2022 8:34 am

Dear Sitangshu,

yes, rlu (reciprocal lattice units) are in 2pi/alat units.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

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