Molecular Interactions Induced by a Static Electric Field in Quantum Mechanics and Quantum Electrodynamics

TL;DR

This paper investigates how a static electric field influences molecular interactions using quantum mechanics and quantum electrodynamics, providing exact solutions and insights into controlling intermolecular forces.

Contribution

It offers a novel exact solution for coupled oscillators under a static field and analyzes the interplay of electrostatics, polarization, and dispersion in different regimes.

Findings

External field controls interaction strength and orientation.

Electrostatic and polarization energies are unaffected in the retarded regime.

Framework combines quantum mechanics and electrodynamics for molecular interactions.

Abstract

By means of quantum mechanics and quantum electrodynamics applied to coupled harmonic Drude oscillators, we study the interaction between two neutral atoms or molecules subject to a uniform static electric field. Our focus is to understand the interplay between leading contributions to field-induced electrostatics/polarization and dispersion interactions, as considered within the employed Drude model for both non-retarded and retarded regimes. For the first case, we present an exact solution for two coupled oscillators obtained by diagonalizing the corresponding quantum-mechanical Hamiltonian and demonstrate that the external field can control the strength of different intermolecular interactions and relative orientations of the molecules. In the retarded regime described by quantum electrodynamics, our analysis shows that field-induced electrostatic and polarization energies remain unchanged (in isotropic and homogeneous vacuum) compared to the nonretarded case. For interacting species modeled by quantum Drude oscillators, the developed framework based on quantum mechanics and quantum electrodynamics yields the leading contributions to molecular interactions under the combined action of external and vacuum fields.