This is one of the standard topics relevant to those who model intermolecular forces, for computer simulation and/or theory of the liquid state. The molecular charge distribution is typically modelled by a multipole expansion (sometimes, by a set of distributed multipoles) and the electrostatic interactions between a pair of molecules are calculated in just the way you describe.

Two of the standard works in the field are The Theory of Intermolecular Forces by Anthony Stone, second edition (Oxford University press, 2013), and Theory of Molecular Fluids by CG Gray and KE Gubbins (Clarendon Press 1984). Both texts are very clearly written, go into great detail, and give formulations based on both Cartesian tensors and spherical tensors.

In both cases, they go much further, discussing induction and dispersion interactions and so on, but these may not be so relevant to your application.

This is one of the topics relevant to those who model intermolecular forces, for computer simulation and/or theory of the liquid state (actually, for gaseous and solid states of matter too). The molecular charge distribution is typically modelled by a multipole expansion (sometimes, by a set of distributed multipoles) and the electrostatic interactions between a pair of molecules are calculated in just the way you describe.

Two of the standard works in the field are The Theory of Intermolecular Forces by Anthony Stone, second edition (Oxford University press, 2013), and Theory of Molecular Fluids by Christopher G Gray and Keith E Gubbins (Clarendon Press 1984). Both texts are very clearly written, go into great detail, and give formulations based on both Cartesian tensors and spherical tensors. The issue of convergence of such expansions is also addressed in both books.

In both cases, they go much further, discussing induction and dispersion interactions and so on, and the way the multipoles may be calculated for real molecules through computational chemistry, but these aspects may not be so relevant to your application.