# Thermostat and barostat

**URL:** <https://gromacs.bioexcel.eu/t/thermostat-and-barostat/3537>\
**Category:** User discussions\
**Created:** [January 25, 2022, 11:32am UTC](https://gromacs.bioexcel.eu/t/thermostat-and-barostat/3537 "2022-01-25T11:32:48Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![rainbow](https://avatars.discourse-cdn.com/v4/letter/r/7993a0/32.png) [@rainbow](https://gromacs.bioexcel.eu/u/rainbow)\
**Post date:** [January 25, 2022, 11:32am UTC](https://gromacs.bioexcel.eu/t/thermostat-and-barostat/3537/1 "2022-01-25T11:32:48Z")

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GROMACS version: 2021.4  
GROMACS modification: No

Dear gmx users,

I wonder if the settings of the thermostat and barostat are dependent on the force field or not.

Is there a proper combination of tcoupl and tau-t, pcoupl and tau-p for each force field?

By testing various combinations of algorithms and coupling times, Can I simply select a combination with a low Err. Est. or RMSD value for temperature or pressure?

For example of a 5 ns production run for a protein-ligand system,

amber99sb-ildn  
rlist = rcoulomb = rvdw = 1.0 nm  
coulombtype = PME  
vdwtype = Cut-off  
fourierspacing = 0.12  
pme-order = 4  
ref-p = 1.0  
constraints = h-bond  
constraint-algorithm = LINCS

case1. V-rescale (0.1 ps) and Parrinello-Rahman (2.0 ps)  
Average temperature = 300.023  
Err.Est. = 0.012  
RMSD = 1.25016  
Tot-Drift = -0.0428242

case2. Nose-hoover (2.0 ps) and Parrinello-Rahman (5.0 ps)  
Average temperature = 299.999  
Err.Est. = 0.0046  
RMSD = 1.23304  
Tot-Drift = 0.0225867

case3. Nose-hoover (0.4 ps) and Parrinello-Rahman (2.0 ps)  
Average temperature = 300.022  
Err.Est. = 0.0068  
RMSD = 1.39488  
Tot-Drift = 0.040256

Is it appropriate to use case 2 out of the above three cases?

If the temperature is well maintained in all three cases, does not have a significant effect on the simulation results no matter what I use?

Please give me some advice.  
Kind Regards,