A Method to Extract Potentials from the Temperature Dependence of Langmuir Constants for Clathrate-Hydrates

It is shown that the temperature dependence of Langmuir constants contains all the information needed to determine spherically averaged intermolecular potentials. An analytical ``inversion'' method based on the standard statistical model of van der Waals and Platteeuw is presented which extracts cell potentials directly from experimental data. The method is applied to ethane and cyclopropane clathrate-hydrates, and the resulting potentials are much simpler and more meaningful than those obtained by the usual method of numerical fitting with Kihara potentials.Comment: 33 pages, 7 figures, to appear in Physica

Low-frequency dielectric functions of dense and chevronic thin films of parylene C

International audienc

Prospects for plasmonic hot spots in single molecule SERS towards the chemical imaging of live cells

Single molecule surface enhanced Raman scattering (SM-SERS) is a highly local effect occurring at sharp edges,} interparticle junctions and crevices or other geometries with a sharp nanoroughness of plasmonic nanostructures ({"}hot spots{"}). The emission of an individual molecule at SM-SERS conditions depends on the local enhancement field of the hot spots{,} as well as the binding affinity and positioning at a hot spot region. In this regard{,} the stability of near-field nano-optics at hot spots is critical{,} particularly in a biological milieu. In this perspective review{,} we address recent advances in the experimental and theoretical approaches for the successful development of SM-SERS. Significant progress in the understanding of the interaction between the excitation electromagnetic field and the surface plasmon modes at the metallic or metallic/dielectric interface of various curvatures are described. New knowledge on methodological strategies for positioning the analytes for SM-SERS and Raman-assisted SERS or the SERS imaging of live cells has been acquired and displayed. In the framework of the extensive development of SM-SERS as an advancing diagnostic analytical technique{,} the real-time SERS chemical imaging of intracellular compartments and tracing of individual analytes has been achieved. In this context{, we highlight the tremendous potential of SERS chemical imaging as a future prospect in SERS and SM-SERS for the prediction and diagnosis of diseases