[CPMD-list] Energy components in PIMD

[Axel Kohlmeyer]

On Fri, 9 May 2008, ukasz Walewski wrote:

LW> BTW there is a jump in the kinetic energy of the ions
LW> (http://bioexploratorium.pl/ljw/cpmd/nvt/cont.nve/EKIONS.png) that is
LW> incomprehensible for me. It appears in the point of the restart and it
LW> seems to me that some aspect of the previous simulation was not
LW> restarted properly. The input that generated the restart is here:

you deleted the VELOCITIES keyword from restart.
without VELOCITIES your ionic velocities will be 
re-initialized to the value of TEMPERATURE (or
the target temperature of the N-H chains). it is 
very likely that your instantaneous temperature was 
not at that value, so you change the kinetic energy
of your system and thus the jump. 

there are few situations where you don't want to
restart from the velocities of the restart.

cheers,
    axel.

LW> http://bioexploratorium.pl/ljw/cpmd/nvt/cont.nve/4mdnve.inp and it
LW> differs from the previous NVT one only by those lines:
LW> 
LW> 3c3
LW> <   RESTART WAVEFUNCTION COORDINATES
LW> ---
LW> >   RESTART WAVEFUNCTION COORDINATES VELOCITIES NOSEE NOSEP ACCUMULATORS
LW> LATEST
LW> 8,11d7
LW> <   TEMPERATURE
LW> <     300.0
LW> <   NOSE IONS MASSIVE
LW> <     300.0  180.8
LW> 
LW> What did I do wrong with the restart ?
LW> 
LW> Thanks,
LW> Lukasz
LW> 

-- 
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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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