unitless water parameters

hi dear users , in manual of lammps for unitless parameters for make charge to unitlessis is written that
charge = reduced LJ charge, where q* = q / (4 pi perm0 sigma epsilon)^1/2
, pi is 3.14159 ? so what is perm0?and how much is the value of perm0 for oxygen or water ?thanks friends

, pi is 3.14159 ? so what is perm0?and how much is the value of perm0 for
oxygen or water ?thanks friends

The zero indicates it might be
http://en.wikipedia.org/wiki/Vacuum_permeability