Abstract
We propose a simple statistical mechanical theory for a strongly dipolar fluid at low densities, based on the analogy between a system of polydisperse linear chains and the equilibrium structure of these fluids as revealed by computer simulations. At low densities, both steric and dipolar interactions between long chains are weak and thus the dipolar fluid is well described as an ideal gas of polydisperse chains. We have further investigated how the residual dipolar interaction between monomers and/or additional isotropic attractions between the spheres cause the dissociation of the chains and/or the condensation of the dipolar fluid.