Mo Haiding, Evmenenko Guennadi, Kewalramani Sumit, Kim Kyungil, Ehrlich Steven N, Dutta Pulak
Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
Phys Rev Lett. 2006 Mar 10;96(9):096107. doi: 10.1103/PhysRevLett.96.096107.
Oscillatory density profiles (layers) have previously been observed at the free surfaces of liquid metals but not in other isotropic liquids. We have used x-ray reflectivity to study a molecular liquid, tetrakis(2-ethylhexoxy)silane. When cooled to T/Tc approximately 0.25 (well above the freezing point for this liquid), density oscillations appear at the surface. Lateral order within the layers is liquidlike. Our results confirm theoretical predictions that a surface-layered state will appear even in dielectric liquids at sufficiently low temperatures, if not preempted by freezing.
