[gmx-users] Dispersion correction in a heterogeneous system

[Mikhail Stukan]

Dear gmx-users,

Although  this task has been already discussed few years ago (http://lists.gromacs.org/pipermail/gmx-users/2007-January/025668.html) the full summary is not clear to me. So I would really appreciate if somebody could give me advice on the following subject.

I am trying to simulate an aqueous solution of NaCl. One of the properties I am interested in is surface tension, which means that correction to the pressure could be quite important.  But the system is heterogeneous: values of C_6 differs from 0.0003 (for Na-Na) to 0.0180 (for Cl-Cl), so they are not comparable. Is it worth to use dispersion correction in such a system? Or such results will have no real meaning and the proper way would be to switch off the dispersion correction and just increase cut-off (or perform rerun with higher cut-off)?

Thanks you very much in advance,
Mikhail

=============================================
Dr Mikhail Stukan
Schlumberger Dhahran Carbonate Research Center,
Dhahran Techno Valley  - KFUPM,
P.O. Box 39011, Dammam / Doha Camp  31942,
Kingdom of Saudi Arabia
Tel: +966 3 331 0300 ext 6182
Fax:+966 3 330 0845
mstukan at slb.com<mailto:mstukan at slb.com>

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