Study of the effects of confinement in the collective excitations of liquid deuterium

The spectrum of collective excitations of liquid deuterium in the bulk and confined within a MCM-41 matrix having pores of an average diameter of 2.4 nm has been studied by means of neutron scattering and molecular dynamics simulations. The main effects of confining liquid D-2 consist in a shift of the characteristic frequencies associated with damped density oscillations to higher energies. A strong decrease in diffusivity is also observed upon confinement.