[QE-users] PDOS Hybridization / Extra State

[Giovanni Cantele]

Hi,
the projections computed by projwfc.x use the atomic orbitals defined in
the pseudopotential files. For example, in the sulfur pseudopotential:
https://pseudopotentials.quantum-espresso.org/upf_files/S.pbe-n-kjpaw_psl.1.0.0.UPF
you can find, among others, the line:
<PP_PSWFC.5 index="5" label="3D" l="2">
This indicates that a d orbital is included in the pseudopotential.
Therefore, observing projections onto S d orbitals does not, by itself,
imply hybridization.
Hybridization can be inferred when a Kohn–Sham state has significant
projections onto multiple atomic orbitals, either of different angular
momentum on the same atom or on different atoms.
In contrast, a state dominated by a single atomic orbital character is not
hybridized.
Regarding Ag: the PDOS on Ag atomic orbitals cannot be strictly zero.
Electronic states originating from (or partially derived from) Ag atomic
orbitals must appear somewhere in the spectrum.
A possible explanation is that you are examining a specific energy range
where the projections onto Ag atoms are negligible.

Giovanni
-- 

Prof. Giovanni Cantele
Dipartimento di Fisica "Ettore Pancini"
Universita' degli Studi di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at unina.it
Phone: +39 081 676910

Web page: https://sites.google.com/view/giovanni-cantele/home


Il giorno ven 13 feb 2026 alle ore 05:01 Tang, Weilun via users <
users at lists.quantum-espresso.org> ha scritto:

> Dear Quantum Espresso users,
>
> I calculated PDOS for a molecule on an Ag layer where the S atom of the
> molecule forms a bond to the Ag layer. I have the following questions:
>
>
>    1. In the output, this S atom has d orbitals. Are these d orbitals
>    representing the hybridization of S and Ag atoms, or did I do something
>    wrong? I used the default value for nbnd in scf and nscf. Below is my input
>    for projwfc.in:
>
>
> ------------------------------------
> &PROJWFC
>   prefix= 'a',
>   outdir= './tmp/',
>   filpdos= 'pdos.dat'
>   emin=-30.0,
>   emax=0,
>   degauss = 0.01
> /
> -------------------------------------
>
>
>    2. Is there a reason why the PDOS for Ag atoms are all 0?
>
>
> Thank you for your time,
>
> Weilun Tang
>
> Department of Materials Science and Engineering
> Iowa State University
>
>
>
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