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

Mousumi Upadhyay Kahaly mousumi at jncasr.ac.in
Thu Jun 30 17:49:57 CEST 2005


This is a resubmission of my last mail, since I'm in real need of help.
=========================================================================

Dear All,

       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
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