Need I change the expression of Coulomb interactions?

Hi,
My Coulomb interactions expreesion is different from the one in lammps. Mine is E=q1q2/(4πεr), while in lammps it is E=Cq1q2/(εr). You can also pay attention to see the two expressions in the attachment.Need I change the expression in the *.cpp and *.h and how to change it? Or needn’t I do it and does the C contain 1/(4π)? And when I use the units of real, should I consider the conversion of unit as the unit of E is Kcal/mol?
Thank you very much!

mine.png

lammps.png

Hi,
   My Coulomb interactions expreesion is different from the one in lammps.
Mine is E=q1q2/(4πεr), while in lammps it is E=Cq1q2/(εr). You can also pay
attention to see the two expressions in the attachment.Need I change the
expression in the *.cpp and *.h and how to change it? Or needn't I do it and
does the C contain 1/(4π)? And when I use the units of real, should I
consider the conversion of unit as the unit of E is Kcal/mol?

set up a test system with only two or three atoms, so you can compute
manually what the numbers should be and then compare with what LAMMPS
computes.

axel.