[lammps-users] Fe-Calculation of ionic liquid and graphite surface

Dear all,
I am using the lammps version - 3march 2020.
I am trying to calculate the free energy difference between an Ionic liquid and Graphite surface. The input file is attached in this email. The nvt part is running fine but after that it is giving an error while using the adapt/fep command.

ERROR: compute fep type pair range is not valid for pair hybrid sub-style (…/compute_fep.cpp:235)

I have calculated free-energy of water and graphite but this kind of error never showed up in that case.

Any help would be appreciated.

Thank you
Devargya

in.lmp.txt (3.26 KB)

Dear all,
I am using the lammps version - 3march 2020.
I am trying to calculate the free energy difference between an Ionic liquid and Graphite surface. The input file is attached in this email. The nvt part is running fine but after that it is giving an error while using the adapt/fep command.

ERROR: compute fep type pair range is not valid for pair hybrid sub-style (…/compute_fep.cpp:235)

I have calculated free-energy of water and graphite but this kind of error never showed up in that case.

Any help would be appreciated.

the error message is quite clear. you are not applying the pair style you are adapting to the atom types that you are listing.
it is impossible to confirm this from the input file alone since this information seems to be set in the data file.

axel.

I am sharing the data file and the pair file. If that helps, i am using lj/cut/coul/long/soft potential where i not = j and lj/cut/coul/long where i = j .

Thank you,
Devargya

pair.lmp (8.29 KB)

data.lmp (672 KB)

like I already guessed, and like the error message clearly states, the issue you are having is because you are trying to adapt different sub-styles at the same time.
you are applying fix adapt/fep and compute fep to “pair lj/cut/coul/long/soft lambda *13 14” but those interactions are not all of that pair style.
this cannot work and hence the (well deserved and correct) error.

axel.