Electric Field-enhanced Intermolecular Bonding: an Ab Initio Density Functional Investigation

Effects of external electric field on some otherwise weakly bound molecular complexes are investigated within the density functional theory. The complexes are comprised of polar and non-polar molecules, which otherwise interact via van der Waals bond, or through a weak hydrogen bond. Applied field distorts the geometry and forces the molecules to come closer to each other leading to a remarkable enhancement in the bonding between the otherwise weakly bonded atoms. We investigate this phenomenon with the density functional theory applied two prototype systems in external electric field, viz. acetylene + water and carbon-dioxide + water systems where the applied field strengthens the bonding, considerably so in the latter case.