Average energy vs Energy of average

[aihaike]

Hey,

When performing Molecular dynamic or Monte Carlo simulation (in NPT or NVT ensemble), I'm wondering whether there is any difference between the average energy of the system and the energy of the average structure.
If there is a difference, how munch should it be? and why?
Does the the energy of the average structure refer to the lattice energy?
Thank you.

 

[Simon Bridge]

Have you tried doing the calculation to find out?
What do you mean by "energy of average structure"?
Were have you seen this term?

Generally the average energy over all states would not be the same as the energy of the average state ... there is no set "should be" difference.

 

[aihaike]

Hey Simon,

Thanks for replying.
During the run I average the geometiers, what I mean by energy of energy of average structure is just the energy of average geometry.
I'm wondering why there is a difference between <U> and the latter, and whether we can estimate the difference.