Dear Lammps users:

After searching the list a lot, I still do not understand how to calculate the free energy of a solid. What I want to calculate is the free energy difference between two structures at different temperatures. Is there a method can be easily used in lammps to obtain this? Thank you!

Dear Lammps users:

After searching the list a lot, I still do not understand how to calculate

the free energy of a solid. What I want to calculate is the free energy

difference between two structures at different temperatures. Is there a

method can be easily used in lammps to obtain this? Thank you!

you'll have better chances searching the published literature and

topical textbooks, like this one:

https://www.amazon.com/Free-Energy-Calculations-Applications-Chemistry/dp/3540736174/ref=mt_paperback?_encoding=UTF8&me=

whether LAMMPS can do what you want is a secondary concern. you first

need to find what methods are applicable at all and only then look

into if and how they are usable from within LAMMPS.

axel.

Thank you.

Actually I would like to use finite difference to calculate the dynamic matrix and then to get the phonon spectrum. I wonder if lammps has such functionality or is there a tutorial for this purpose?

Thank you.

Actually I would like to use finite difference to calculate the dynamic

matrix and then to get the phonon spectrum. I wonder if lammps has such

functionality or is there a tutorial for this purpose?

now that is a *very* different question from what you had asked

before. in that case you can move to step 2. have you looked at the

documentation? there is a package called USER-PHONON (wink, wink,

nudge, nudge, ...)

axel.