Apply pressure to the simulation box

User discussions
1

Hi,
How can the pressure be applied to the simulation box along the z direction?

2

Hi maryam,

Have a look at the semiisotropic option here:
https://manual.gromacs.org/documentation/current/user-guide/mdp-options.html#pressure-coupling

If you use that type of pressure coupling, you have to set two refernce pressure values and two compressibilities - one in the xy direction and one for z.

Then you can fix the compressibility in the xy-direction to a zero and only give a compressiblity in the z-direction (the second compressilbity value to enter), effectively allowing scaling of the box only in z-direction.

3

Hi “cblau”
thanks for your guidance.

4

I read part of an article on this subject : “The simulations were performed under a given
constant hydrostatic pressure in the NVT ensemble, it can be obtained by an additional acceleration to every molecule along the z direction”.Do you think, it is a different strategy?

5

Hi Maryam,

Yes, this is a different strategy. With the strategy that I outlined above, there is no sense of up or down, the system is “squeezed” to keep the pressure from both sides, wheres in the case that you describe, particles get a constant force “upwards” or “downwards”

6

thanks