Switching-off the collective dynamics of liquid water upon immersion of golden nanoparticles

We have investigated how the propagation of sound-like modes in liquid water is affected by the presence of nanoparticles at low concentration. Inelastic X ray scattering spectra clearly show the drastic effect of the immersion of 50 nm sized golden nanoparticles on the collective dynamics of room temperature water, despite the very diluted character of the suspension. By using a Bayesian approach implemented through a Reversible Jump - Markov Chain Monte Carlo algorithm, the data analysis provided evidence about the switching-off of the water THz dynamics and that only the excitations propagating inside the nanoparticles survive in the solution. These results may open new perspectives on the design and development of new materials, especially when the tuning of the heat transport properties needs to be implemented.