Dynamics of Electron-Transfer-Mediated Decay in a Weakly Bound Trimer

Reduction of ions is an important process in many areas of science, including surface physics and radiation biology. In weakly bound matter, such as clusters or liquids, neutralization can occur with the explicit involvement of atoms or molecules in the local environment of the ion. Among the possible pathways, electron-transfer-mediated decay (ETMD) is particularly efficient in such systems. In ETMD, charge and energy are transferred to neighboring species, leading to the reduction of the multiply ionized atom. Although studied for more than a decade, important aspects of this nonlocal process remain unclear, including the role of nuclear dynamics and the influence of geometry. Here, we investigate the NeKr₂ trimer after core ionization of the Ne atom. We perform fully dimensional nuclear dynamics combined with ETMD decay rate calculations and introduce a new 1/R⁶ asymptotic expression for the decay width. We assess the competition between ETMD, which leads to Coulomb explosion, and direct dissociation without ETMD. We quantify the efficiency of ETMD in asymmetric configurations of the trimer, where charge transfer occurs along the shorter Ne-Kr distance, while energy transfer proceeds along the longer one. The generality of the ETMD mechanism makes it highly relevant in weakly bound environments such as clusters and liquids, where its efficiency increases substantially with the number of neighbors.