For 𝐹 4125, 0123 (𝑧) = 𝐶𝑒 ,!/9 % , the corresponding density distribution is calculated as 𝜌(𝑧) = 𝜌 7 𝑒 ,9 % FGH([,!/9 % ]/(< & L) . That is, the apparent density decreases near the solid surface. The XRR analysis also proved that the liquid molecules show a lower density near the solid surface in 1-3 nm on PDMS/Si interface. They considered the low-density layer detected by XRR and the highly elastic layer observed by QENS to be identical, which is widely known as the "immobilized layer" . Therefore, the increase in 𝐹 4125,0123 near the solid surface would reflect either a lower density or the increased elasticity near the solid surface, or both, which are strongly related to each other.