Dear all:
I have tried to calculate the absorption spectrums of semiconductors using yambo. I find that the lines become smooth, when I set a large range of DMRngeXd.
I think it need a convergence test for DmRngeXd. It's right?
But I confuse how to set the firt value of DmRngeXd.
For LiF tutorial, in 02_RPA_no_LF:
% DmRngeXd
0.10000 | 0.30000 | eV # [Xd] Damping range
in 06_BSE:
% BDmRange
0.15000 | 0.30000 | eV # [BSS] Damping range
For 2D_Si_surface tutorial, in 02_RPA_no_LF_par:
% DmRngeXd
0.030000 | 0.10000| eV # [Xd] Damping range
I need your help. Thanks.
Tieyu Lu
How to set the values of DmRngeXd
Moderators: Davide Sangalli, andrea.ferretti, myrta gruning, andrea marini, Daniele Varsano, Conor Hogan
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How to set the values of DmRngeXd
Tieyu Lu
Physics Department of Xiamen university (China)
Physics Department of Xiamen university (China)
- Daniele Varsano
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Re: How to set the values of DmRngeXd
Dear Teyu Lu,
this is not a parameter that have to be carried to convergence.
It is an artificial damping that it is useful to add in order to compare with experiments.
The results of your calculations are excitations energies and oscillator strengths, and you are
not calculating line widths while in experiments the widths are determined by lifetimes and
finite resolutions. So, the range of the damping is a parameter that you can adjust for
your needs.
Cheers,
Daniele
this is not a parameter that have to be carried to convergence.
It is an artificial damping that it is useful to add in order to compare with experiments.
The results of your calculations are excitations energies and oscillator strengths, and you are
not calculating line widths while in experiments the widths are determined by lifetimes and
finite resolutions. So, the range of the damping is a parameter that you can adjust for
your needs.
Cheers,
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/
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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- Posts: 12
- Joined: Sat Oct 31, 2009 10:25 am
Re: How to set the values of DmRngeXd
Dear Daniele:
Thank you for your reply.
I find that when I use a large range damping, it needs less kpoints to get a smooth line of absorption spectrum.
So I can use less kpoints with a large range damping to simulate absorption spectrum. It is OK ?
Best wish
Tieyu Lu
Thank you for your reply.
I find that when I use a large range damping, it needs less kpoints to get a smooth line of absorption spectrum.
So I can use less kpoints with a large range damping to simulate absorption spectrum. It is OK ?
Best wish
Tieyu Lu
Tieyu Lu
Physics Department of Xiamen university (China)
Physics Department of Xiamen university (China)
- Daniele Varsano
- Posts: 3824
- Joined: Tue Mar 17, 2009 2:23 pm
- Contact:
Re: How to set the values of DmRngeXd
Dear Tieyu Lu,
of course with a large damping you are smoothing the spectrum,
but remember that your smoothing is artificial, and with a small
k-point sampling you could miss some physics.
bests,
Daniele
of course with a large damping you are smoothing the spectrum,
but remember that your smoothing is artificial, and with a small
k-point sampling you could miss some physics.
bests,
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/
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/
-
- Posts: 12
- Joined: Sat Oct 31, 2009 10:25 am
Re: How to set the values of DmRngeXd
Dear Daniele:
Thank you for your reply.
Tieyu Lu
Thank you for your reply.
Tieyu Lu
Tieyu Lu
Physics Department of Xiamen university (China)
Physics Department of Xiamen university (China)