Dear Xiupeng,<br><br>What you're seeing is the difference between <span style="font-style: italic;">freezing </span>water and <span style="font-style: italic;">overcooling </span>it. If you want your water to crystallize, you'll actually have to make it - e.g., by putting it in contact with ice. Normally, pure water doesn't freeze on its own, you can easily verify this experimentally at home :)<br>
<br>Best regards,<br>Vasilii<br><br><div><span class="gmail_quote">2008/4/19, Wei, Xiupeng <<a href="mailto:xiupeng-wei@uiowa.edu">xiupeng-wei@uiowa.edu</a>>:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi gmx users,<br> I'm a new Gromacs user. Till now, I can get pretty good simulation of ice melting to water, but why can't I simulate water freezing to ice?<br> The .top and .gro files used for water freezing simulation are generated by ice melting to 310K. I changed the temperature in .mdp file to 230K, but after mdrun, the water was still water, it can't freeze?<br>
How can I get water freezing to ice?<br> I paste mdp for your reference.<br> Thanks.<br> <br> best,<br> xiupeng<br> <br> <br> title = icing at 230 K with cuffoff<br> cpp = /lib/cpp<br>
integrator = md<br> ;Time step<br> dt = 0.002<br> nsteps = 100000<br> ;Output control<br> nstxout = 100000<br> nstvout = 100000<br> nstlog = 100<br>
nstenergy = 100<br> nstxtcout = 100<br> ;Neigbour searching<br> nstlist = 10<br> ns_type = grid<br> rlist = 0.8<br> ;Non bonded interaction<br>
coulombtype = pme<br> optimize_fft = yes<br> fourierspacing = 0.2<br> pme-order = 6<br> ewald-rtol = 1e-05<br> rcoulomb = 0.8<br> vdw-type = Cut-off<br>
rvdw = 0.8<br> DispCorr = EnerPres<br> ;Temperature coupling<br> tcoupl = berendsen<br> tc-grps = System<br> tau_t = 0.1<br> ref_t = 230<br>
;Pressure coupling<br> pcoupl = berendsen<br> pcoupltype = isotropic<br> tau_p = 1.0<br> compressibility = 5e-5<br> ref_p = 1.0<br> <br> gen_temp = 230.0<br>
constraints = all-bonds<br> ; generate velocities<br> gen_vel = yes<br> gen_seed = 173529<br> <br> <br> _______________________________________________<br> gmx-users mailing list <a href="mailto:gmx-users@gromacs.org">gmx-users@gromacs.org</a><br>
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