# 回复： The temperature, press and total energy output are"-nan", what is wrong?

Hi Axel

Thank you. I solved my problem by reconstructing the initial configuration.

You suggest me to notice the “very high potential energy”, and atoms being placed on top of each other can lead to “very high potential energy”. I think the value of the potential energy depends on the system, but from your answer, there seems to be a normal range of the potential energy. If so, What is this range?

Fan Li

Hi Axel

Thank you. I solved my problem by reconstructing the initial configuration.

You suggest me to notice the "very high potential energy", and atoms being
placed on top of each other can lead to "very high potential energy". I
think the value of the potential energy depends on the system, but from
your answer, there seems to be a normal range of the potential energy. If
so, What is this range?

you can infer this from the potential energy function, which depends
on the individual model.
for lennard-jones, for example, the potential energy is only positive,
when atoms are very close and thus very repulsive.
thus the total potential energy should be negative unless you have an
extremely high-pressure, high-density and/or high-temperature system.
similarly, for coulomb, the potential for opposite signed atoms is
always negative and for equal signed atoms always positive. atoms will
arrange according to their polarity, thus you are more likely to have
a negative potential energy.

thus for a system with your potential functions under normal
circumstances you should have a negative potential energy and not a
strongly positive one.

axel.

I understand.
Thank you.

Fan Li

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