Yambo Community Forum

Posted: **Sat Jun 04, 2022 4:15 am**

Dear Yambo community

I compiled Yambo5.1.0 on my Centos7 workstation with Intel ONEAPI 2021.3.0. I am now following the tutorial on calculation of Si band gaps (http://www.yambo-code.org/wiki/index.php?title=Silicon)

I could repeat the Hatree Fock section, but failed to repeat the "COHSEX without empty bands" secton. In the "W-size convergence" subsection, no matter what the "NGsBlkXs" was, I always got the same "[Hatree-Fock] Direct Gap", which was about 8.320753 eV. This result was quite different from the one of the tutorial.

And I noticed in the "parse_gap.sh" script that, the band gap was defined as

Code: Select all

......
   VBMo=`grep " 1.000" $i/References/$1 | grep " 4.0000" | grep " 0.000" | awk '{print $3}'`
   VBM=`grep " 1.000" $i/References/$1 | grep " 4.0000" | grep " 0.000" | awk '{print $4}'`
   CBMo=`grep " 2.576" $i/References/$1 | grep " 5.000" | awk '{print $3}'`
   CBM=`grep " 2.576" $i/References/$1 | grep " 5.000" | awk '{print $4}'`
   case "$1" in 
    *-01HF*)
      echo  ${NK[$j]} $VBMo $VBM $CBMo $CBM | awk '{print $1 " " $5-$3 }' >>  "$2"
      ;;
    *)
      echo  ${NK[$j]} $VBMo $VBM $CBMo $CBM | awk '{print $1 " " $4+$5 }' >>  "$2"
      ;;
   esac
......

Should the band gap be $4+$5-($2+$3)?

Thanks!

Posted: **Mon Jun 06, 2022 5:35 pm**

Dear lysea82,

please sign your post with your name and affiliation, this is a rule of the forum and you can add your signature once for all in your user profile.

no matter what the "NGsBlkXs" was, I always got the same "[Hatree-Fock] Direct Gap", which was about 8.320753 eV.

Please note that NGsBlkXs do not affect the HF gap, which does not depend on the size of the dielectric matrix.

About the parse script, please note they are very old, it is possible that there are mistakes or that they are not suitable anymore with the new format output and should be corrected. Just pay attention that HF and COhsex output it is possible they do not contain the same information (Eqp and correction) anyway this is reported in the legend.

Best,

Daniele

Posted: **Fri Jun 10, 2022 12:13 pm**

Dear Daniele

Thank you very much for your replies. Also I added my signature to the post.

Regards

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