[Wien] Convergence problem

Laurence Marks L-marks at northwestern.edu
Mon Dec 29 00:16:56 CET 2014


Also, only 1 k-point (Gamma), an RMT and RKMax similar to what you use for
bulk Ni, particularly as I assume you are doing the calculation to get an
enthalpy of formation. You may have to use the mpi versions as it is
probably too large for a non-mpi run.

If you are doing WC+U (or -ineece) the U (or on-site hybrid) removes the
phase transition so convergence should be simple.

Straight WC is not a simple calculation because the physics for an isolated
Ni atom is wrong. With wrong physics there is in fact no guarantee that the
calculation will ever converge!

___________________________
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu
MURI4D.numis.northwestern.edu
Co-Editor, Acta Cryst A
"Research is to see what everybody else has seen, and to think what nobody
else has thought"
Albert Szent-Gyorgi
On Dec 28, 2014 11:47 AM, "Laurence Marks" <L-marks at northwestern.edu> wrote:

> You almost certainly need to run spin polarized, probably MSR1 (GREED
> 0.1), TEMPS (room temp). The convergence is complicated for WC (& simple
> GGAs) due to an electronic phase transition between sp & d occupation near
> the fixed point.
>
> ___________________________
> Professor Laurence Marks
> Department of Materials Science and Engineering
> Northwestern University
> www.numis.northwestern.edu
> MURI4D.numis.northwestern.edu
> Co-Editor, Acta Cryst A
> "Research is to see what everybody else has seen, and to think what nobody
> else has thought"
> Albert Szent-Gyorgi
> On Dec 28, 2014 10:47 AM, "Muhammad Sajjad" <sajjadpu at gmail.com> wrote:
>
>>  Dear Users
>> I am running SCF calculation for Ni with lattice constant of 30 Bohr and
>> using WC-GGA. The calculation is not converging even upto 100 iterations
>> and more. To solve the problem I have performed following steps
>>
>>  switched to TEMPS = 0.005 from TETRA
>> Changed MSR1 to PRATT
>> changed mixing factor (increase and decrease from 0.2)
>>
>>  Thanking in advance.
>>
>>  Dr. Sajjad
>>
>>
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