[Pw_forum] how to calculate and plot HOMO or LUMO isosurface

[Filipe Camargo Dalmatti Alves Lima]

Dear Zhan,

The number of electrons on your system determines the occupied bands and
consequently the HOMO level.

So, What you need to do?

First, check the number of electron that you are using. (If you are using
the O default pseudopotencials it should be 6 valence electrons)
Then, you'll have 12 electrons and 6 bands (each bands is occupied by 2
electrons).

Now check your output file, which is generated using the pw.x code.
The band number 6 represents your HOMO level and the band number 7 is the
LUMO one.

So, now you know your bands. Then you can obtain the wavefunction.

You will need to run the pp.x twice: one for HOMO and another for LUMO.
kband=6 (to plot HOMO)
and
kdand=7 (to plot LUMO)

I hope it will solve your problem,

Best regards,


-- 
_________________________________________
Filipe Camargo Dalmatti Alves Lima
PhD Student
University of São Paulo, Physics Institute, Materials Physics Department,
Nanomol Group, Brazil.
Phones:    (11) 3091-6881  (USP)
                (11) 8249-4628 (TIM)



On Wed, Jul 25, 2012 at 2:13 AM, Franklin Zhan <zhanhit at hotmail.com> wrote:

>  Dear PWSCF users,
> I am trying to calculate HOMO and LUMO levels and plot these isosurfaces
> for O2 molecule.
> I first relaxed the O2 and then did nscf calculation. then I used pp.x to
> calculate the HOMO and LUMO levels. but I can not find the HOMO or LUMO
> level in output files.
> the code for pp.x is pasted as following:
>
> &inputpp
>     prefix= 'O2'
>     outdir= '/scratch/zhan0273/PWSCF/O2/tmp'
> filplot = 'O2'
> plot_num= 7
> spin_component=0
> ! kpoint=40
> kband=8
> /
> &plot
> nfile = 1
> filepp(1) = 'O2'
> weight(1) = 1.0
> iflag = 3
> output_format = 5
> fileout = 'O2.orb.xsf'
> /
>
> So please give advice. Thank you all in advance!
>
> Best regards,
>
> ------------------------------
> Franklin Zhan
> Ph.D student
> School of Mechanical and Aerospace Engineering,
> Nanyang Technological University, Singapore.
>
>
>
>
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>
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