The mechanism of action of inhalation anaesthetics such as N2O and the inert gases are unclear. Direct binding to receptor sites on membranes would rely on weak intermolecular interactions. A plausible alternative is an indirect effect though changes in the dynamics of the lipids forming the membranes in which the receptors are anchored. Previous experiments have established that the chain dynamics in DOPC are altered subtly upon exposure to N2O. Xe is a more potent anaesthetic than N2O, indeed a safe breathing mixture will give general anaesthesia. Consequently this proposal seeks to determine whether a DOPC bilayers exposed to Xe shows a more pronounced effect on the dynamics of the lipids. Furthermore, methyl oleate will be used as a model to give the anisotropic hyperfine coupling constant required to simulate the previously collected ALC-mSR spectra.