[lammps-users] Polarization calculation in Lammps

Dear users,

I am a new Lammps user and I want to know if there is any way to compute the polarization (macroscopic or other) as output from Lammps calculation. I checked the manual, you can apply electric fields but it is strange that there is nothing related to polarization, electric potential, electric potentials outputs,…

Thank you in advance for your help.


I have written a small code (fix dipole) which calculates the dipole moment components and total dipole moment of a group of atoms. Although i do not guarantee the the correctness of the result i believe it is working fine. Let me know if you need it. The instantaneous volume can be added to get the polarization directly.


The version of LAMMPS we plan to release later this month will have an
atom style that puts a point-dipole on each atom. Also a dipole-dipole
potential and an integrator that changes the orientation of the dipoles
due to induced torques. Not really polarization, but related to it ...


That sounds pretty exciting... will it allow for arbitrary pair
interactions (i.e., any potential energy function that depends on the
relative position and the orientations of two atoms), or only the specific
case of electric dipole interactions?


The new version will have several particle types that
support orientation (dipole, granular, ellipsoid) and
integrators that assume a torque has been computed.

The potentials that produce torque will include dipole/cut,
granular, and gay-berne (for ellipsoidal LJ particles). So
you could add a new pair potential that produces torque
and use one of those integrators.