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.