[Pw_forum] Temperature continuously going down in cp.x run

[vega lew]

Dear sir,

Did you ask whether the (etot+ekinc) conserve during the dynamic process?

I sum the corresponding columns. I found it is not changing very much.

For example, the (ekinc+ etot) is -4369.40879 (-4369.44669+0.0379) at 2200
step.
Then it changes to -4369.41514 (-4369.45479+0.03965) at 2300 step.
And it sometimes goes a little up and sometimes a little down. But the value
is in range of
-4369.41 and -4369.45.

thank you for reading.

vega


On Fri, Nov 27, 2009 at 2:02 AM, Stefano de Gironcoli <degironc at sissa.it>wrote:

> is the total  (kinetic + potential)  energy conserved ?
> stefano
>
> vega lew wrote:
> > dear all,
> >
> > I want to calculate certain heterogeneous reaction on a solid surface.
> > First input the initial structure from previous pw.x relaxations.
> > Second I fixed ions and let electron damping calculation run;
> > Then un-fixed the ions and let both electron  and ions damping
> > calculations run.
> > Third I gave a random motion to the atoms in the system with
> > amprp(1)~(3) = 0.01
> > and then repeated second step to bring the system to the ground state.
> > Fourth I added temperature (300K) to the system, using verlet schedule.
> >
> > But the temperature continuously going down, from 1000K to 150K during
> > the fisrt 3000 steps.
> > I think there might be something wrong with my cp.x calcuation.
> > Do you think the amprp(1)~(3) = 0.01 of random motion is too small?
> >
> > Here is the input of my dynamics process,
> >  &CONTROL
> >
> >                        title = 'CP'
> > ,
> >                  calculation = 'cp'
> > ,
> >                 restart_mode = 'restart'
> > ,
> >                       outdir = '/disk5/nanjing/vega/cp/300/' ,
> >                       wfcdir = '/tmp/'
> > ,
> >                   pseudo_dir =
> > '/home/software/nanjing/vega/espresso-4.0.1/pseudo/' ,
> >                       prefix = 'cp_molecular' ,
> >                        nstep = 99999 ,
> >                           dt = 10,
> >                       iprint = 5,
> >                        isave =
> > 150,
> >  /
> >
> >  &SYSTEM
> >
> >                        ibrav =
> > 8,
> >                    celldm(1) =24.8624,
> >                    celldm(2) = 0.8520,
> >                    celldm(3) = 1.6964,
> >                          nat =
> > 147,
> >                         ntyp = 3,
> >                         nr1b = 20,
> >                         nr2b = 20,
> >                         nr3b = 20,
> >                         nbnd =
> > 630,
> >                    ecutwfc   =   30,
> >                    ecutrho   =  300,
> >  /
> >
> >
> >  &ELECTRONS
> >            electron_dynamics = 'verlet',
> >  /
> >
> >  &IONS
> >
> >                 ion_dynamics = 'verlet'
> >              ion_temperature = 'nose',
> >                        tempw = 300,
> >  /
> > ..................
> > ..................
> >
> > best wishes,
> >
> > vega
> >
> > --
> >
> ==================================================================================
> > Vega Lew ( weijia liu)
> > Graduate student
> > State Key Laboratory of Materials-oriented Chemical Engineering
> > College of Chemistry and Chemical Engineering
> > Nanjing University of Technology, 210009, Nanjing, Jiangsu, China
> >
> ******************************************************************************************************************
> > Email: vegalew at gmail.com <mailto:vegalew at gmail.com>
> > Office: Room A705, Technical Innovation Building, Xinmofan Road 5#,
> > Nanjing, Jiangsu, China
> >
> ******************************************************************************************************************
> >
> > ------------------------------------------------------------------------
> >
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> >
>
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-- 
==================================================================================
Vega Lew ( weijia liu)
Graduate student
State Key Laboratory of Materials-oriented Chemical Engineering
College of Chemistry and Chemical Engineering
Nanjing University of Technology, 210009, Nanjing, Jiangsu, China
******************************************************************************************************************
Email: vegalew at gmail.com
Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing,
Jiangsu, China
******************************************************************************************************************
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