How to determine compressibility?

User discussions
#1

GROMACS version:2020.2
GROMACS modification: Yes/No

Dear all,

I am trying to run an npt calculation for a pure organic solvent system. How to determine the compressibility then?

Many thanks in advance.

Make solvent box
#2

Hi,

you can calculate isothermal compressibility

  1. by calculating volume fluctuation. < volume fluctuation > _NPT= V * k_B * T * isothermal compressibility (see p 53 chapter Fluctuations Allen Tildesley Book "computer simulation of liquids)
  2. by running NVT simulation at slightly different volume and applying
    isothermal compressibility = - 1/V * (dV/dP)_T

Kind regards
Alessandra