Is the energy converged in NVE simulation?

[zuohen... at gmail.com]

Hello everyone,

Recently, I want to confirm the suitable time step, when I use core shell 
model for OH- ions and SPC/Fw for water molecules. 
I have tested if I use core shell model for water, 1 fs of time step is too 
large. The energy of NVE simulation is not converged significantly.
However, after I transfered the SPC/Fw to replace the core-shel model for 
water, the energy of NVE simulation seemed to be converged (shown in 
figure, blue line for the energy plot and orange line for the averaged 
energy).
There are 1 Fe3+, 3 OH-(core shell model) and 28 water molecules(SPC/Fw) in 
the system. 
I am not sure if the energy is converged? or the fluctuation is too strong? 
If it is converged, can I use 1 fs of time step to do next simulation?
Could anyone give me some suggestions?

Thank you very much!!

Best,
Zuoheng  

[image: Fe3OH3.png] <about:invalid#zClosurez>
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