Dielectric constant by finite electric fields in Gaussian. A work in progress.
You want to calculate dielectric constants for molecules with Gaussian? Good! So do we.
This work makes use of the finite electric field within the Gaussian vacuum electronic-structure code (see http://www.gaussian.com/g_tech/g_ur/k_field.htm ), and then trying to work back to a dielectric constant within the PEAD framework (see https://cms.mpi.univie.ac.at/vasp/vasp/EFIELD_PEAD_tag_Finite_electric_fields.html )
It's a work in progress. There might be fundamental mathematic problems, and technical issues.