A fluxional anionic water trimer

We explore the energy landscape of anionic water clusters using Car–Parrinello molecular dynamics with a proper self-interaction correction. While neutral water trimers preserve a ring structure over long time periods, significant changes in the structure of their anionic form, (H2O), occur at temperatures above 100 K. These rearrangements are such that the excess electron attaches and spatially localises close to a new form of double-acceptor water molecule. Such structural rearrangement arises from cooperation among the dipole moments of each single water molecule within the cluster. We discuss the excess electron's attachment to water clusters up to 21 molecules, rationalising the structural binding motifs needed to bind it.