I am using GROMACS to run molecular dynamics simulations of pure liquids, in the NpT ensemble at room temperature and p = 1 atm. My first test was with isopropanol (also known as 2-propanol). I used about 500 molecules in a cubic box with size equal to 4 nm. I adopted the OPLS force-field, and my topology file was generated using LigParGen server. However, I am having problems with some results of my simulations. It thermalizes and describe well the liquid density and molar volume, however it predicts a Heat capacity $C_{p}$ greater than two times the experimental value. The isothermal compressibility is very wrong also. I don't know Where am I going wrong, does anyone have any idea what it could be?
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