Molecular dynamics of NH3 induced by core-electron excitation

Abstract

Nuclear motion in the N1s⁻¹4a¹₁ core-excited state of ammonia is investigated by studying the angular anisotropy of fragments produced in the decay of the highly excited molecule and compared with predictions from ab initio calculations. Two different fragmentation channels (H⁺/NH₂⁺ and H⁺/NH⁺/H) reveal complex nuclear dynamics as the excitation photon energy is tuned through the 4a₁ resonance. The well-defined angular anisotropy of the fragments produced in the dissociation of the molecular dication species suggests a very rapid nuclear motion and the time scale of the nuclear dynamics is limited to the low fs timescale.