[Pw_forum] Pw_forum Digest, Vol 27, Issue 47

[Lorenzo Paulatto]

In data 11 settembre 2009 alle ore 15:23:39, Shaptrishi Sharma  
<sh.shapt at gmail.com> ha scritto:
> My nband value is 122 as my total number of atoms are 66 .of which 21
> Hydrogen.And if I remove the option nelup and neldw, I got it as "too  
> many bands are not converged" thus I increased my vaccum, however it  
> still
> remains the same.

Dear Shaptrishi,
 from the file Doc/INPUT_PW.txt

    Variable:       nelec

    Type:           REAL
    Default:        the same as ionic charge (neutral cell)
    Description:    number of electron in the unit cell
                    (may be noninteger if you wish)

as you see, nelec is the total number of electrons, not only the ones from  
hydrogen. Accordingly, a few lines later you should have found:

    Variables:      nelup, neldw

    Type:           REAL
    Description:    number of spin-up and spin-down electrons, respectively
                    Note that this fixes the final value of the  
magnetization.
                    The sum must yield nelec that must also be specified
                    explicitly in this case. Not valid for spin-unpolarized
                    or noncollinear calculations, only for LSDA.  
Obsolescent:
                    use multiplicity or tot_magnetization instead.

it says quite clearly that nelec=nelup+neldw, again nelec is the total  
number of electrons.

best regards




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Lorenzo Paulatto
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