Competition between Proton Transfer and Electron-Transfer-Mediated Decay in a Microsolvated Environment

We investigate the relaxation dynamics of the 1s-ionized state of the Li+ ion in microsolvated Li+(H2O)n (n = 1, 2) cluster, which decays via an intermolecular electron-transfer-mediated decay (ETMD) process. For Li+H2O, the ETMD decay rates are evaluated as a function of Li–O separation. The results reveal a pronounced distance dependence of the ETMD lifetime, reflecting the nonlocal nature of the decay. To probe solvent effects, ETMD is also examined in Li+H2S. The ETMD decay rate is computed using a highly correlated Fano equation-of-motion coupled-cluster singles and doubles (Fano-EOMCCSD) method. In Li+(H2O)2, we identify proton transfer as a highly competing relaxation pathway. By evaluating ETMD decay widths at frozen nuclear geometries sampled along the nuclear dynamics trajectories, we elucidate how changes in cluster geometry and hydrogen-bond rearrangements modulate the instantaneous propensity of the ETMD process during proton transfer.