Permittivity of free space and the Permeability of free space in the real unit

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1

Dear users LAMMPS

I have a plane electromagnetic filed so I can define the magnetic field according to the electric field by Maxwell’s equations but I need to know the Permittivity of free space and the Permeability of free space in the real unit of lammps.
How can I find them in the real unit?

I searched in the manual and Mailing list but I did not find anything.

best wishes
Mohammad

2

please see:
https://lammps.sandia.gov/doc/dielectric.html

and
https://lammps.sandia.gov/doc/pair_coul.html

The value of the constant C for the difference choices of units in the expressions of the latter manpage can be found as “qqr2e” in the function Update::set_units().
Any custom code should use that constant (i.e. force->qqr2e when converting interactions between charges to energies (or for forces use force->qqrd2e which is force->qqr2e/force->dielectric)) as do all current styles in LAMMPS that compute energies or forces resulting from interactions between charges.

Axel.