We request 6 days on IRIS to investigate the rotational and long timescale dynamics of the [Li(NH3)4]+ unit in the series of halide materials Li(NH3)4X (X= Cl, Br, I). This proposal is tied to POLARIS proposal and is a continuation of recent IRIS Xpress time (Proposal number 1310285).A variable temperature QENS study across both the tunnelling and stochastic regimes would be able to determine the following:1)Low temperature examination of tunnel splitting in Li(NH3)4X and sensitivity to low temperature changes. 2)Relation of the tunnel splitting observed to INS librations measurements (already collected on TOSCA) and thus to [Li(NH3)4]+ geometry ¿ targeting the dynamics of individual NH3 environments within the system. 3) Detailed elastic window scans.