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rlu to a.u. conversion

Posted: Wed Nov 16, 2022 7:37 am
by sitangshu
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,

Re: rlu to a.u. conversion

Posted: Wed Nov 16, 2022 8:34 am
by Daniele Varsano
Dear Sitangshu,

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

Best,
Daniele