Comparison of the low frequency vibrational profile of deep eutectic solvents based on urea and tetraalkylammonium cations with varying degrees of symmetry. Architectural differences will be understood through the analysis of collective modes – which inform on the degree of order in the mixture, intermolecular stretching modes and environment-sensitive internal modes, such as methyl torsions. Specifically, we aim to compare:a) pairs of eutectic systems based on tetraalkylammonium cations which differ in their degree of symmetry while retaining similar enthalpic profiles;b) annealed and shock-frozen samples, to ascertain whether the eutectic mixtures form ordered or disordered solids below the eutectic temperature c) each mixture with its pure components;d) fully hydrogenated and partially deuterated mixtures