how can I modify my input file in order that I will be able to read Highest and Lowest Unoccupied orbitals (HOMO and LUMO) in output file either in scf or relax calculations?
I think you have to do bands and dos calculations
from dos vs energy graph you can know the band gap or from BANDS plot you get information regarding band gap
I have seen some output files in which HOMO and LUMO are explicitly calculated.
this is from pwscf forum link
If you know the number of bands in your system, say n, you simply set
nbnd=n+1 in your pw.x calculation. In the output you should already see the
energy you are looking for. Then you should refer to the documentation for
the input of pp.x,
http://www.quantum-espresso.org/wp-content/uploads/Doc/INPUT_PP.html
I think what you will be using is plot_num=7
http://pw_forum.pwscf.narkive.com/fCf8viuy/homo-lumo-calculations
If you specify the nbnd value in your pw.x input file, the HOMO and LUMO values will be printed in the output file. YOu need to choose nbnd, depending on your system, pw.x documentation says;
for an insulator, nbnd = number of valence bands (nbnd = # of electrons /2); for a metal, 20% more (minimum 4 more)
can you tell me how I should define nbnd value for semiconductors? S. Assa Aravindh
best regards
Dear Ahadzadeh you may choose nbnd as half number of electron s for semiconductor. You will het the no. electron from the output file of scf calculation.
@Shabnam Ahadzadeh ..for semiconductors also you can do the same as insulators
A. Z. Ziauddin Ahmed and S. Assa Aravindh
thank you for your response and consideration..
Thank you all for your suggestions. But how do you display the HOMO and LUMO for a doped-nanotube? For a pristine nanotube, you just add the nbnd and set the occupations to fixed but that doesn't work for a doped nanotube. Regards
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