Dear All, I have a question that is afflicting me and I would be glad if you can give me an answer. I have a dipole in vacuum put at a certain distance from the surface of a dielectric material. I know the entity of the dipole, I know the distance from the surface and I know the interaction energy between the dipole and the material. How can I calculate the dielectric constant of the material? I hope that the problem is clear. Thanks for the attention Kind Regards Franky P.S. It's not properly an homework but since it was a problem I thought posting it here was the right thing to do. My problem is that I cannot find an equation relating my data in the books I have even if I know it should be possible to do that.