ethanol.index (291 Bytes)
ethanol.mol (423 Bytes)
ethanol.parm (547 Bytes)
npt_3000_0.7.log (34.2 KB)
npt_3000_0.7.txt (847 Bytes)
water_ethanol_box_3000_0.7.data (1.9 MB)
Dear LAMMPS users,
I am performing NPT simulations of ethanol-water mixtures using the TIP4P model for water and the OPLS-UA model for ethanol. The total number of molecules is fixed at 3000, and I varied the ethanol mole fraction across five values: 0.05, 0.10, 0.15, 0.20, and 0.70.
For mole fractions up to 0.20, the final density obtained after equilibration agreed well with experimental values (within 1–2% error). However, for the highest ethanol mole fraction of 0.70, the simulated density was 0.75 g/cm³, which is significantly lower than the experimental value of ~0.85 g/cm³.
The following files are attached:
[ethanol.index|attachment](upload://8eCnjOBgJFikGNDdyiV4W6UYpNK.index) (291 Bytes) [ethanol.mol|attachment](upload://8sTHMbfmZS8XryWsIMwbcT443r8.mol) (423 Bytes) [ethanol.parm|attachment](upload://iyiIZh1VFtgJDkiuSuSLideWDs7.parm) (547 Bytes) [npt_3000_0.7.log|attachment](upload://wiAT4lVSO1xyTcGZ3YtE5891JeD.log) (34.2 KB) [npt_3000_0.7.txt|attachment](upload://ojylSu2BIqcz1I1OIzDPWMNIpGR.txt) (847 Bytes) [water_ethanol_box_3000_0.7.data|attachment](upload://2TyCqd0ORjDhAcDn0Jsa9BJAVYQ.data) (1.9 MB)water_ethanol_box_3000_0.7.data
– Structure file for 3000 molecules at 70% ethanolnpt_3000_0.7.txt
– LAMMPS input script for NPT equilibration at 315 K, 1 atmnpt_3000_0.7.log
– Log file showing temperature, pressure, and density over timeethanol.mol
– Ethanol molecule templateethanol.parm
– Parameter file for ethanol (pair, bond, angle, dihedral definitions)
Why does the density decreases?
Thank you very much in advance for your support.
asas