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Re: [abinit-forum] total energy calculation


Chronological Thread 
  • From: "Rajdeep Saha" <rsaha@pas.rochester.edu>
  • To: forum@abinit.org
  • Subject: Re: [abinit-forum] total energy calculation
  • Date: Wed, 3 Aug 2005 00:27:18 -0400 (EDT)
  • Importance: Normal


Hi,

Comment out the getwfk -1 ( restore default), it makes sense to use it in
a multi dataset mode.Also replace "acell:" with "acell".

Hope this helps.

Rajdeep Saha


> Dear abinit user:
> When I try to calculate the total energy of two atoms at ground state,
> the abinis version 4.4.3 break off undesignedly. The error message in
> the log file is:
> vtowfk : BUG For istwf_k=2, observed the following element of evec :
> 3 1 nan nan
> with a non-negligible imaginary part.
> Action : contact ABINIT group.
>
> Delivered 6 WARNINGs and 0 COMMENTs to log file.
>
> leave_new : decision taken to exit ...
>
> with warnings like:
> scfcge: WARNING -
> Potential-based CG line minimization has trouble to converge.
> The algorithm is restarted with more secure parameters.
>
> I've changed the iscf from default 5 to 3, but it didn't work.
> Do I need to change some parameters? I appreciate any advice.
>
>
>
> Input file:
> # C-O potential energy calculation
> #
>
> #Definition of the unit cell
> acell: 40 34 34 # The keyword "acell" refers to the
> # lengths of the primitive vectors (in Bohr)
>
> #Definition of the atom types
> ntypat 2 # There is only one type of atom
> znucl 8 6 # The keyword "znucl" refers to the atomic number of the
> # possible type(s) of atom. The pseudopotential(s)
> # mentioned in the "files" file must correspond
> # to the type(s) of atom. Here, the only type is
> Hydrogen.
> nband 10
> getwfk -1
>
> #Definition of the atoms
> natom 2 # There are two atoms
> typat 1 2 # They both are of type 1, that is, Hydrogen
> xcart
> -3.85 20.0 20.0
> 3.85 20.0 20.0
> #Definition of the planewave basis set
> ecut 30.0 # Maximal plane-wave kinetic energy cut-off, in Hartree
>
> #Definition of the k-point grid
> nkpt 1 # Only one k point is needed for isolated system,
> # taken by default to be 0.0 0.0 0.0
>
> #Definition of the SCF procedure
> #iscf 3
> nstep 1000 # Maximal number of SCF cycles
> toldfe 1.0d-12 # Will stop when, twice in a row, the difference
> # between two consecutive evaluations of total energy
> # differ by less than toldfe (in Hartree)
> diemac 1.0 # Although this is not mandatory, it is worth to
> # precondition the SCF cycle. The model dielectric
> diemix 0.5 # function used as the standard preconditioner
> # is described in the "dielng" input variable section.
> # Here, we follow the prescriptions for molecules
> # in a big box
>
>


--
Rajdeep Saha
Department of Physics & Astronomy
University of Rochester
Hutchison Hall 428
Phone:(585)273-5687(office)
(585)317-1578(mobile)
email:rsaha@pas.rochester.edu





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