[Pw_forum] minimization in CP molecular dynamics

[Mansoureh Pashangpour]

Dear Nicola
I've got experience with CP for H2O.
It is simple but I couden't
find the best way to run CP for my system

On Thu, Jul 10, 2008 at 12:28 PM, Mansoureh Pashangpour <
mansourehp at gmail.com> wrote:

> Dear Nicola
> Is it related to nstep
> I chose nstep  = 5000,
> should it be more or less ?
>
>
> On Thu, Jul 10, 2008 at 12:21 PM, Nicola Marzari <marzari at mit.edu> wrote:
>
>> Mansoureh Pashangpour wrote:
>> > dear Nicola
>> > this is ekinc for end of minimization I found it small after verlet
>> dynamics
>> >  ekinc         :        0.10064       0.10064 (AU)
>> >  ekin          :      144.72166     144.72166 (AU)
>> >    epot          :     -473.07863    -473.07863 (AU)
>> >    totel energy  :     -280.01088    -280.01088 (AU)
>> >
>> > why they are different with
>> >  > scf:  total energy              =  -243.33284101 Ry
>>
>>
>> It is actually (very) large, and it needs to be well below 10-5 au.
>>
>> If after that it's still different, try something easy - a hydrogen
>> molecule, and go from there.
>>
>> In any case, the fact that the cp calculation has a much lower energy
>> than pwscf means that probably something incorrect is going on. As
>> mentioned, try very simple things, and move up from there.
>>
>>
>>                                nicola
>>
>> --
>> ---------------------------------------------------------------------
>> Prof Nicola Marzari   Department of Materials Science and Engineering
>> 13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
>> tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu
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>
>
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