Much of our understanding of e - aq 's dynamics has come from one-electron mixed quantum classical (MQC) simulations, which consider the quantum mechanics only of the excess electron, while treating the solvent molecules classically. The low computational cost of MQC methods has allowed for converged sampling of the equilibrium properties and dynamics of e - aq , as well as its nonadiabatic dynamics following photoexcitation. Nevertheless, an underlying approximation in all current MQC descriptions of e - aq is that water's electronic structure and thus intramolecular potential energy surface is unchanged from the neat liquid. MQC is thus inherently incapable of addressing the question of whether the excess electron is a spectator, since it is assumed to be.