Gradient Bundle Analysis of Electric Field Induced Changes in Electron Charge Density

Applying an electric field (EF) to a molecule is knownto inducerearrangement of its electron charge density, rho-(r). Previous experimental and computational studies have investigatedeffects on reactivity by using homogeneous EFs with specific magnitudesand directions to control reaction rates and product selectivity.To best incorporate EFs into experimental design, a more fundamentalunderstanding of how EFs rearrange rho-(r) is necessary.To gain this understanding, we first applied EFs to a set of 10 diatomicand linear triatomic molecules with various constraints on the moleculesto determine the importance of rotation and altering bond lengthson bond energies. In order to capture the subtle changes in rho-(r) known to occur from EFs, an extension of the quantum theoryof atoms in molecules called gradient bundle (GB) analysis was employed,allowing for quantification of the redistribution of rho-(r) within atomic basins. This allowed us to calculate GB-condensedEF-induced densities using conceptual density functional theory. Resultswere interpreted considering relationships between the GB-condensedEF-induced densities and properties including bond strength, bondlength, polarity, polarizability, and frontier molecular orbitals(FMOs).