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Re: [lammps-users] Energy rise
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Re: [lammps-users] Energy rise


From: Chuanxing Zhan <chuanxingzhan@...16...>
Date: Fri, 4 May 2018 16:54:32 +0000 (UTC)

Thanks for your advice. I did the test. The energy doesn't change if I keep the same time step, it will rise if I increase the time step. I also agree with your point, the energy result should not relate to time step. I don't think I changed any other parameter in my scripts.

Kerwin


On Friday, 4 May 2018, 11:32:10 AM GMT-5, Valerio Sorichetti <valeriosorichetti@...24...> wrote:


Dear Kerwin,

I would say that changing the timestep shouldn't give that result, but why don't you test it yourself? 
Try to do the same without changing the timestep and see whether the problem persists.

Valerio

2018-05-04 18:14 GMT+02:00 Chuanxing Zhan <chuanxingzhan@...16...>:
It did happen at restart process. And the only change is time step. When I turned  the time step form 1fs to 2fs, the energy of system rose.  Is that the problem?
On Thursday, 3 May 2018, 5:42:49 PM GMT-5, Valerio Sorichetti <valeriosorichetti@...24...> wrote:


Dear Kerwin,

Does this happen as soon as you restart the simulation?
If this is the case, such a sudden increase in the energy could come from a change in the the mass of a group of atoms, or in the parameters of the some interaction potential (or in those of a bond type).
Check that you are not changing anything important when restarting the simulation.

Valerio

2018-05-04 0:09 GMT+02:00 Chuanxing Zhan via lammps-users <lammps-users@...396... sourceforge.net>:
Dear Lammps Users,

Hello, everyone. I used the lammps to equilibrium small organic system. The system seems equilibrated after a long simulation period under npt ensemble. However, when I continued to run the simulation, the energy increase at a point and enter to equilibration again. Dose anyone know what happen with the system, or is this result reliable? Any help would be appreciated.

Kerwin


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