QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: ams_nanolab on June 21, 2016, 08:01

Title: To converge optical spectra
Post by: ams_nanolab on June 21, 2016, 08:01
What's the rule of thumb to converge optical spectra w.r.t. the no. of bands to be included above and below the Fermi level? If I look for spectra in the range of 0-5 eV, so it should include all the bands within -2.5 eV to +2.5 eV ? But I have noticed if there are say 100 bands in the energy range and I go on increasing even more bands (say 200-300) the spectra still changes, although so many bands may not be even present in the said energy range. What am I missing?  ???
Title: Re: To converge optical spectra
Post by: Ulrik G. Vej-Hansen on June 21, 2016, 10:07
It depends somewhat on your system, but we have seen cases where it is necessary to go to more than 30 eV above the Fermi level. There is not a 1-to-1 correspondence between the energy of your photons and the energy range which is necessary to investigate.
Title: Re: To converge optical spectra
Post by: ams_nanolab on June 21, 2016, 11:55
Yes, that seems to be the case. Thanks  :)