This utility computes static dielectric permittivity (dielectric constant) from fluctuations of the total molecular momenta using expression (S.W.deLeeuw, J.W.Perram, E.R.Smith, Ann.Rev.Phys.Chem., 37, 245 (1986)):
where is the dipole moment of molecule and the sum is taken over all the molecules. Note that this formula is applicable only for small and rigid (or almost rigid) molecules. It is important that the molecules were not broken by the periodic boundary conditions.
f77 -O3 -o diel diel.f tranal_base.f
This utility needs only a single parameter - the temperature, which should be written directly after the trajectory parameters.