[CP2K-user] The temperature I get is different from what I set when do massive and global thermostat.

[Julian Heske]

Hello,

in order to run a MD calculation at a specific tempertare, you have to 
equilibrate the system first to reach your target temperature. The time you 
need to equilibrate your system is dependent on your initial configuration. 
Since you are starting with a structure which has a very high potential 
energy (-157,5 vs. ~ -168 a. u. of the others, see out.txt), this energy 
remains as kinetic energy in the system and the thermostat will need a long 
time to remove the energy from the system. You can first do a geometry 
optimization ( CP2K_INPUT <https://manual.cp2k.org/trunk/CP2K_INPUT.html> / 
MOTION <https://manual.cp2k.org/trunk/CP2K_INPUT/MOTION.html> / GEO_OPT 
<https://manual.cp2k.org/trunk/CP2K_INPUT/MOTION/GEO_OPT.html> ), which 
leads to an optimized structure. Then start your MD run with your obtained 
structure as initial configuration. However, you should then still take a 
look at the temperature and not use the equilibration steps for your 
analysis.

Kind regards,
Julian
tang... at gmail.com schrieb am Freitag, 26. März 2021 um 15:16:33 UTC+1:

> Dears cp2k's users,
>       I'm doing a vibration analysis exercise.When I did massive and 
> global thermostat, the temperature I get is different from what I set. 
> Could you tell me what causes this error? I would appreciate you generous 
> help. The input and output file are listed as follow.
>
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