Ultrafast Relaxation Dynamics of Inner-Shell Vacancies in Hydrated Pyrrole

Abstract

We employ real-space, real-time time-dependent density functional theory (TDDFT) combined with Ehrenfest dynamics to investigate ultrafast intermolecular relaxation following inner-valence ionization in hydrated pyrrole. This time-dependent approach treats electronic and nuclear motions simultaneously, allowing the description of electronic excitation, charge transfer, ionization, and nuclear motion.When the initial vacancy in the O 2s 1 state is created on the water molecule, the system predominantly undergoes intermolecular Coulombic decay (ICD) and electron-transfer mediated decay (ETMD), accompanied by pronounced charge transfer between pyrrole and water. In contrast, ionization of the pyrrole site for N 2s electron leads to both ICD and Auger decay channels. These results demonstrate that the decay dynamics are strongly governed by the initial vacancy location, offering microscopic insight into intermolecular energy-transfer mechanisms in hydrated molecular systems.