[Pw_forum] Understanding "eband" & "deband" in "total energy"

[Konstantin Kudin]

 Things look to be rather tricky in electrons.f90 ...

 There is some density that is generated from new bands, and then there
is also this density mixed with the older ones via the Broyden scheme
for which the potential is actually calculated.

 In principle, one should be able to get the total energy and all its
components for a given density. However, it is not clear if the
subroutine "electrons" actually does this.

 So I would also like to know what is the total energy in "electrons",
and which density it corresponds to.

 Kostya

 

--- Mousumi Upadhyay Kahaly <mousumi at jncasr.ac.in> wrote:

> Dear Sir,
> 
>        I wanted to know how the final "total energy" is calculated
> for the
>  PWSCF output file and what each of those terms line "one-electron
> contribution" etc meant.
> 
>        As the source code "electrons.f90" in PW directory shows,
> 
>        etot    = eband + ( etxc - etxcc ) + ewld + ehart + deband +
> demet
> 
>        After writing "etot", also other terms like "one-electron
> contribution", "hartree contribution" etc are written by,
> "
>         WRITE( stdout, 9060 ) &
>             eband, ( eband + deband ), ehart, ( etxc - etxcc ), ewld
> "
> 
>        I am having problem to understand the terms "eband" and
> "deband".
> How the "deband" value is assigned? When we solve the Kohn-Sham
> equation, the
> energy eigen values obtained are band energies, right? From K-S
> equation how do I obtain all above terms?
> 
>        May I please know (1) from where can I find the details of all
> these terms and their explanations and (2) how each of them will
> contribute to the cohesive energy of a system?
> 
>        Best regards,   mousumi.
> 
> 
> 
> > On Tuesday 28 June 2005 10:14, Mousumi Upadhyay Kahaly wrote:
> >> [...] total energy is being obtained if we add other terms except
> "band
> energy sum" i.e. total energy = "one-electron contribution" +
> "hartree
> contribution" + "xc contribution" + "ewald contribution" +
> "correction for
> metals ".
> >>        Any help to understand this is appreciated.  regards.
> mousumi.
> > For the definiiton of the various terms, see
> >   http://www.democritos.it/pipermail/pw_forum/2003-May/000291.html
> > and
> >   http://www.democritos.it/pipermail/pw_forum/2003-May/000293.html
> > Paolo
> > --
> > Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
> > Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513
> Piazza
> dei Cavalieri 7      I-56126 Pisa, Italy
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://www.democritos.it/mailman/listinfo/pw_forum
> 
> 
> 
> 
> 
> 
> 
> 
> 
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