Exploring Molecular Equilibrium Geometries in Static and Quantized Fields

Experimental studies have shown that external electromagnetic fields can offer a means to modify molecular structure and reactivity. In this work, we derive and implement analytical molecular gradients at the Hartree–Fock level for both static and quantized electromagnetic fields to explore the field effects on equilibrium geometries. We investigate the equilibrium geometries and field-induced orientations of representative molecules: water, the water dimer, and corannulene. Our analysis reveals distinct field-induced effects: shifts in the equilibrium geometry of water under a combined cavity and static electric field; a reduction in the inversion barrier of corannulene in the presence of quantized or magnetic fields; and orthogonal orientation of the individual water molecules in the water dimer with respect to the quantized field component.