At the other extreme, we consider the bulk am-LPS, represented by the unstructured purple square in Figure , and find that hACF ! Q i decays rapidly over a period of 46 ns. In the homogeneous amorphous regime, we can see that as the amorphous PS 4 backbone changes across the simulation, Li atoms experience continually changing electronic environments, and thus we can think of the Li atoms moving in a "glass-like" ensemble of sites embedded in PS 4 environments. At a 46 ns decay rate, ⌧ SAE is outside of the range detectable by a real SAE experiment which would, at best, yield a small residual coupling b > 0 (see Equation ). In a fast ion conductor, we expect this rapid decay of the hACF ! Q i, however this is the first time we are able to accurately quantify the rate of this decay in an amorphous material, highlighting the importance of this UFP+ML-EFG approach.