[Wien] Slab convergence
Lukasz Plucinski
pluto at physics.ucdavis.edu
Mon Sep 13 14:36:58 CEST 2010
Hello,
I copied newest version of Wien2k (previously I was using version 08). I
would really prefer to avoid compiling a new version, thus I just copied
(overwritten) the binaries (executables) into the root Wien directory.
However, not everything seems to work now...
First I tried to calculate bulk Au as a test. Automatic RMT procedure
has determined the RMT as 2.5 although it should be around 2.72... I
don't understand why but this does not really change much.
First warning appears when running lstart:
WARNING: R0 for atom 1 Z= 79.00 too big
There is no problems with leaking charge:
TOTAL CORE-CHARGE: 54.000001
TOTAL CORE-CHARGE INSIDE SPHERE: 53.999826
TOTAL CORE-CHARGE OUTSIDE SPHERE: 0.000175
Then the rest of initialization goes fine and there is no problem with
convergence. I can also calculate the band structure, however, not the
option of partial charges. Trying to calculate partial charges gives the
following error:
Commandline: x lapw2 -band -qtl -up
Program input is: ""
forrtl: severe (256): unformatted I/O to unit open for formatted
transfers, uni
t 15, file /local/WORK/Au-bulk-no-SO/Au-bulk-no-SO.tmpup
Image PC Routine Line Source
lapw2 082CDBED Unknown Unknown Unknown
lapw2 082CD165 Unknown Unknown Unknown
lapw2 08288C98 Unknown Unknown Unknown
lapw2 08252AFA Unknown Unknown Unknown
lapw2 0825241B Unknown Unknown Unknown
lapw2 08279804 Unknown Unknown Unknown
lapw2 080899EE outp_ 207 outp.f
lapw2 0807B3AF l2main_ 1710 l2main_tmp_.F
lapw2 08083AFB MAIN__ 545 lapw2_tmp_.F
lapw2 080482A1 Unknown Unknown Unknown
lapw2 082D8E30 Unknown Unknown Unknown
lapw2 08048161 Unknown Unknown Unknown
0.324u 0.097s 0:00.42 97.6% 0+0k 0+2224io 0pf+0w
Doing all this on my Fe1Au20 slab gives the same "WARNING: R0 for
atom 1 Z= 79.00 too big" warning, and then during SCF run the
programs gets stuck on a first LAPW2, it does not give the error, but
the LAPW2 continues forever... Thus probably there is something wrong
with my LAPW2, or perhaps my Wien2k_10 is not properly installed.
I will keep working to solve this, but I am sure your suggestions will help.
Regards,
Lukasz
On 9/12/2010 3:37 PM, Laurence Marks wrote:
> N.B., of course when you compare to the number of k-points for bulk Au
> remember to use the primitive cell volume.
>
> On Sun, Sep 12, 2010 at 8:21 AM, Laurence Marks
> <L-marks at northwestern.edu> wrote:
>> Some comments:
>>
>> 1. 100 k-points for a surface is a lot. What I suggest you do is
>> determine how many k-points you need per reciprocal nm^3 (i.e. the
>> multiple of the 3 numbers after "div:" in line 1 of case.klist and the
>> cell volume) for a bulk calculation then use the same density for a
>> surface.
>>
>> 2. Are you using TETRA? I recommend TEMPS for surfaces with a
>> temperature factor of 0.0018 (room temperature).
>>
>> 3. DO NOT REDUCE THE MIXING FACTOR (better called MIXING GREED) unless
>> you understand what you are doing. For old PRATT and BROYD methods
>> this was correct, for MSEC1 it is fundamentally wrong. Too large a
>> mixing greed (say 0.5) is being too greedy, but the algorithm in fact
>> prevents this from happening. To small a greed and the algorithm will
>> starve to death.
>>
>> 4. In 98% of cases where the calculation does not converge this is
>> because something is wrong in the physics of the model, i.e. bad
>> functional or incorrect structure. Possibly the Fe atom is too far
>> from the surface -- have you set FOR in case.in2 and looked at how big
>> these are? With care, you can run a minimization with something like
>> -fc 4 -ec 0.001 at first, then improve these later.
>>
>> 5. When you say it is not converging what do you really mean? The
>> default -ec 0.0001 is very strict for a surface (with incorrect
>> positions), realise that the energy convergence should scale as
>> something like the number of atoms (or the square root of this).
>>
>> 6. Are you using 10.1 and iterative mode? 10.1 is noticeably better
>> and I prefer to use -noHinv.
>>
>> On Sun, Sep 12, 2010 at 7:26 AM, Lukasz Plucinski
>> <pluto at physics.ucdavis.edu> wrote:
>>> Hello,
>>>
>>> I am trying to calculate 1ML of Fe on top of Au(001).
>>>
>>> It was no problem to calculate 20ML slab of Au(001), it converged after 37
>>> iterations with mixing 0.1, 100k-points and all other standard settings,
>>> also using "spin-polarized" calculation mode. I use 50 A of the unit cell
>>> dimension, to have appropriate amount of vacuum.
>>>
>>> However, when I put 1 Fe atom on top of one side of the slab the calculation
>>> didn't converge after 100 iterations (I did couple of trials). I also tried
>>> to increase the cutoff to -8 Ry, and the calculation is running now,
>>> however, no convergence indications after 35 iterations.
>>>
>>> My slab is not relaxed, and the distance between Fe and Au (3.295 au) is
>>> taken from the old publication of Freeman JMMM 75, 201 (1988).
>>>
>>> Automatic RMT distance procedure has put all RTM to 2.5, however, this way
>>> there is a lot of space between Au atoms. I think its better to use 2.72 for
>>> Au atoms and 2.34 for Fe atom -- is there any problem with this ? Neither
>>> setting helps the convergence...
>>>
>>> Maybe I could decrease the amount of k-points to have faster iterations with
>>> even lower mixing parameter ?
>>>
>>> Regards,
>>> Lukasz
>>> _______________________________________________
>>> Wien mailing list
>>> Wien at zeus.theochem.tuwien.ac.at
>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>>
>>
>>
>> --
>> Laurence Marks
>> Department of Materials Science and Engineering
>> MSE Rm 2036 Cook Hall
>> 2220 N Campus Drive
>> Northwestern University
>> Evanston, IL 60208, USA
>> Tel: (847) 491-3996 Fax: (847) 491-7820
>> email: L-marks at northwestern dot edu
>> Web: www.numis.northwestern.edu
>> Chair, Commission on Electron Crystallography of IUCR
>> www.numis.northwestern.edu/
>> Electron crystallography is the branch of science that uses electron
>> scattering and imaging to study the structure of matter.
>>
>
>
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