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CSVR thermostat energy

Posted: Wed Mar 12, 2025 2:41 pm
by paulanatalia_abufager

Hello,
I am using VASP 6.5.0 with the CSVR thermostat and noticed that SP = 0.00E+00 and SK = 0.00E+00 in the output. I was wondering if this is simply an issue with writing the thermostat energy or if there is another explanation. Any information on this would be greatly appreciated.
thanks
Paula Abufager


Re: CSVR thermostat energy

Posted: Thu Mar 13, 2025 7:34 am
by martin.schlipf

Please provide a complete set of input files so that we can investigate this issue. Does this happen in general independent of the structure you consider or only for the particular system you are interested in? Please consider the instructions in the wiki on how to get a minimal reproducible example.


Re: CSVR thermostat energy

Posted: Thu Mar 13, 2025 8:31 am
by paulanatalia_abufager

Dear Martin,
Please find attached all input files, along with the output REPORT file, where you can see that the recorded thermostat energy is 0.
I am observing the same behavior in all calculations: the thermostat energy remains at zero.
However, the kinetic energy is computed, and after many MD steps, the system appears to be thermalized.
Best,
Paula


Re: CSVR thermostat energy

Posted: Thu Mar 13, 2025 9:28 am
by martin.schlipf

I can reproduce that these energies are 0. This seems to be intentional. In dynconstr.F, if you look at the end of the STEP_CSVR routine, EPS and ES are explicitly set to 0. These are exactly the energies that are then written to the OUTCAR file. The call to ENERGY_OUT (which writes to REPORT) in the same routine explicitly passes 0 for these two energies.

Note that this behavior is also observed for MDALGO=1, 3 or 13. Only the Nose thermostats print a nonzero value. This aligns with the text in the OUTCAR where it says nose potential and nose kinetic.