Quantum framework for describing retarded and nonretarded molecular interactions in external electric fields

We employ various quantum-mechanical approaches for studying the impact of electric fields on both nonretarded and retarded noncovalent interactions between atoms or molecules. To this end, we apply perturbative non-perturbative methods within frameworks quantum mechanics (QM) as well electrodynamics (QED). In addition, to provide a transparent physical picture different types resulting interactions, stochastic electrodynamic approach based zero-point fluctuating field. Atomic response properties are described via harmonic Drude oscillators - an efficient model system that permits analytical solution has been convincingly shown yield accurate results when modeling non-retarded intermolecular interactions. The obtained energy contributions classified field-induced (FI) electrostatics, FI polarization, dispersion interplay these three enables manipulation molecular dimer conformations by applying transversal longitudinal along axis. Our framework combining four complementary theoretical paves way toward systematic description improved understanding molecules subject external vacuum fields.