[Pw_forum] smearing

[Iurii TIMROV]

Dear Maxim, Dear All,

> yes, you can. In order to do so, one has to comment the following (two)
> lines in PW/input.f90:
>
>      IF( calculation /= 'nscf' ) CALL errore( 'iosys', &
>          'tetrahedra should be used only for calculation of DOS', 1 )
>

These lines are present in PW/input.f90 of espresso-4.2.1

In espresso-4.3a you will find somewhat different:

! replace "errore" with "infomsg" in the next line if you really want
! to perform a calculation with forces using tetrahedra
!
IF( lforce ) CALL errore( 'iosys', &
   'force calculation with tetrahedra not recommanded: use smearing',1)

> Mind, that 'tetrahedra' has to be used for DOS or SCF only, forces and
> stresses are
> not reliable it this case (they are not variational).

Could you recommend some paper where this statement was
mentioned/discussed/proved? Thanks!

Best regards,
Iurii Timrov


Iurii TIMROV
Doctorant (PhD student)
Laboratoire des Solides Irradies
Ecole Polytechnique
F-91128 Palaiseau
+33 1 69 33 45 08
timrov at theory.polytechnique.fr