Moreover, the widths of the solute-correlated spectra can be observed to be slightly smaller than those of the bulk spectra. Not only that, the widths of the solute-correlated spectra display a decrease with increasing Au NP concentration. Broadening of a peak, under usual experimental conditions, can most often be primarily associated with structural flexibility. Thus, the narrower solute-correlated spectra may suggest the presence of solvation shells around the NPs that are structurally more ordered than the bulk phase. Greater structural rigidity should be taken to be an indication of greater strength of the hydrogen-bonding interactions that are left over.