[Wien] Forces and SO

Fri Dec 18 08:37:36 CET 2015

This is on schedule since long time, but 3 attempts have failed so far ....

On 12/18/2015 08:32 AM, Fecher, Gerhard wrote:
> Dear Peter,
> I am curious -- not only just because of the previous discussion -- whether there are any plans to implement forces with SO
>
> More interesting, the problem might also come up if calculating phonons for high Z materials, or indeed, in their structural optimizatiuon if free parameters exist.
>
> Ciao
> Gerhard
>
> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> "I think the problem, to be quite honest with you,
> is that you have never actually known what the question is."
>
> ====================================
> Dr. Gerhard H. Fecher
> Institut of Inorganic and Analytical Chemistry
> Johannes Gutenberg - University
> 55099 Mainz
> and
> Max Planck Institute for Chemical Physics of Solids
> 01187 Dresden
> ________________________________________
> Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Peter Blaha [pblaha at theochem.tuwien.ac.at]
> Gesendet: Freitag, 18. Dezember 2015 07:57
> An: A Mailing list for WIEN2k users
> Betreff: Re: [Wien] Molecular dynamics using Wien2k
>
> As mewntioned before, the   -so option is wrong. One cannot calculate
> forces with SO in wien2k. Maybe you meant:  -sp    for a spin-polarized
> calculation.
>
> case.finM will be enerated automatically from the forces of a
> scf-calculation. Using   -so you did not calculate forces, ....
>
> MOLD is in my opinion fairly useless, as the average kinetic energy
> (Temperature) will solely depend on your starting geometry and is
> basically "undefined". "Every" MD simulation in literature uses a
> thermostat, mostly the NOSE method and a predefined
> "temperature"(although I admit that we have not followed better
> thermostat developments in recent years).
>
> I also admit, that I have not done any MD run for years, mainly because
> MD in dense packed solids is often of quite limited use because in
> solids very often "nothing happens" at realistic temperatures and
> accessable time scales. Please think carefully about your intended
> application and what you really want to obtain from a MD simulation.
> Otherwise you just burn cpu hours.
>
> And finally, as MD runs would be very expensive, think about your system
> and if an all-electron method like wien2k is necessary and efficient.
> wien2k can compete in speed, if the spheres are large, but can become
> rather expensive if small spheres are needed (like with organic
> molecules, short bonds like in CO, OH, ...)
>
> Am 18.12.2015 um 06:50 schrieb Gavin Abo:
>> I haven't tried MD with min_lapw.
>>
>> The case.finM should be created by the script min_lapw [
>> http://zeus.theochem.tuwien.ac.at/pipermail/wien/2006-May/007135.html ].
>>
>> One of the other users might know better, but it looks like your
>> "min_lapw -p -so" command does not look right.
>>
>> I suggest you run in the terminal the command: min_lapw -h
>>
>> I'm not seeing an option for '-so' in the output from that command.
>>
>> Since you did not use '-j', it looks like the script uses "run_lapw -I
>> -fc 1. -i 40" by default (whereas '-sp' should use "runsp_lapw -I -fc 1.
>> -i 40" by default).
>>
>> For SO, you probably need to use the "-j" option:
>>
>> min_lapw -p -j "runsp_lapw -I -so -fc 1. -i 40"
>>
>> or it looks like there is the '-m' option that will extract force-input
>> and execute mini (without JOB) and exit.
>>
>> On 10/23/2003 8:03 PM, Guo-ping Zhang wrote:
>>> Dear Wien2k users,
>>>
>>> I am interested in using Mini to run MD. After reading the manual and
>>> old mailing list, I could not find a workable example. For instance,
>>> the manual has an example for NOSE (case.inM) not for MOLD. In the
>>> structure optimization section,  all the examples are used for
>>> minimization (which works well for my problem using MSR1a option in
>>> case.inm though the mixer is very slow).
>>>
>>> I tried to use min_lapw -p -so (after a prior successful SCF)  but
>>> failed, since it needs case.finM (but the manual does not say how to
>>> get case.finM). I already looked at haupt_cad.f, which seems to work.
>>>
>>> Has anyone succeeded using Wien2k to run MD?
>>>
>>> If so, is it possible to share with me some details how this is done?
>>>
>>> I would appreciate any hints.
>>>
>>>
>>> Thanks a lot in advance!
>>>
>>> Guoping
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>> SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>
> --
> --------------------------------------------------------------------------
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
> Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
> WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
> --------------------------------------------------------------------------
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>

-- 

                                       P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
--------------------------------------------------------------------------