The frequency-domain infrared spectrum of ammonia encodes changes in molecular dynamics caused by a DC electric field

Significance Our experiment captures the detailed sequence of molecular processes that occur when a uniquely strong (∼108 V/m) direct current (DC) electric field is imposed on ammonia molecules isolated in a solid Ar matrix. Electric fields are of singular importance in chemistry, materials science, and molecular biology. Intermolecular interactions, resulting in rearrangements of electrons and nuclei, are driven by strong electric fields. The detailed responses of molecules to external electric fields of interatomic strength are incompletely understood, because techniques for applying such strong DC electric fields and observing the molecular responses to these fields do not yet exist. Ammonia, with its extreme amplitude intramolecular dynamics and extreme sensitivity to electric fields, is an ideal subject for study by DC-infrared 2-dimensional spectroscopy.