Browsing by Author "Pershan, Peter"
Now showing items 1-20 of 144
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4He Liquid-Vapor Interface Below 1 K Studied Using X-Ray Reflectivity
Penanen, Konstantin; Fukuto, Masafumi; Heilmann, Ralf K.; Silvera, Isaac F.; Pershan, Peter S. (American Physical Society, 2000)The free surface of thin films of liquid helium adsorbed on a solid substrate has been studied using x-ray reflectivity. The film thickness and interfacial profile are extracted from the angular dependence of measured ... -
Absolute Measurement of the Critical Behavior of the Smectic Elastic Constant of Bilayer and Monolayer Smectic-A Liquid Crystals on Approaching the Transition to the Nematic Phase
Fisch, M. R.; Pershan, Peter S.; Sorensen, L. B. (American Physical Society, 1984)A new technique which provides an absolute measurement of the smectic elastic constant B is presented. This technique measures second sound on samples whose top surface is an air—liquid-crystal interface. The free surface ... -
Absolute Measurement of the Critical Properties of Second Sound at the Smectic-A-to-Nematic Phase Transition in 8OCB
Fisch, M. R.; Sorensen, L. B.; Pershan, Peter S. (American Physical Society, 1981)Light scattered from the driven free surface of the smectic-A phase of octyloxy cyanobiphenyl (8OCB) provides a low-frequency measurement of second sound. This yields an absolute measurement of the smectic elastic constant, ... -
Alignment and Defect Structures in Oriented Phosphatidylcholine Multilayers
Asher, Sanford A.; Pershan, Peter S. (Elsevier, 1979)The alignment of dilauryl-, dimyristoyl-, and dipalmitoylphosphatidylcholine at various water concentrations into large oriented monodomain multilayers by annealing at elevated temperatures (Powers and Clark, 1975, Proc. ... -
Amphiphilic Molecules and Liquid Crystals
Pershan, Peter S. (EDP Sciences, 1979)A brief description of the essential features of amphiphillic molecules will be presented. This will be followed by a discussion of specific physical phenomena and their relation to a number of contemporary research areas. ... -
Anomalous Layering at the Liquid Sn Surface
Shpyrko, Oleg G.; Grigoriev, Alexei Yu.; Steimer, Christoph; Pershan, Peter S.; Lin, Binhua; Meron, Mati; Graber, Tim; Gerbhardt, Jeff; Ocko, Ben; Deutsch, Moshe (American Physical Society, 2004)X-ray reflectivity measurements on the free surface of liquid Sn are presented. They exhibit the high-angle peak, indicative of surface-induced layering, also found for other pure liquid metals (Hg, Ga, and In). However, ... -
Anomalous Temperature Dependence of the Elastic Constant B at the Smectic-to-Nematic Phase Transition in Binary Mixtures of Hexyloxycyanobiphenyl-Octyloxycyanobiphenyl (60CB-80CB)
Fisch, M. R.; Sorensen, L. B.; Pershan, Peter S. (American Physical Society, 1982)In hexyloxycyanobiphenyl-octyloxycyanobiphenyl (60CB-80CB) binary mixtures displaying reentrant behavior, the smectic elastic constant, B, deviates from a simple power law of the form \(B=B_1(T_{NA}-T)^{\varphi}\) and ... -
Atomic-Scale Surface Demixing in a Eutectic Liquid BiSn Alloy
Shpyrko, Oleg G.; Grigoriev, Alexei Yu.; Streitel, Reinhard; Pontoni, Diego; Pershan, Peter S.; Deutsch, Moshe; Ocko, Ben; Meron, Mati; Lin, Binhua (American Physical Society, 2005)Resonant x-ray reflectivity of the surface of the liquid phase of the Bi43Sn57 eutectic alloy reveals atomic-scale demixing extending over three near-surface atomic layers. Because of the absence of an underlying atomic ... -
Brillouin Light Scattering Measurement of the Elastic Properties of Aligned Multilamella Lipid Samples
LePesant, Jean-Pierre; Powers, L.; Pershan, Peter S. (National Academy of Sciences, 1978)Brillouin measurements of the elastic properties are presented for aligned multilamella samples of both pure dipalmitoyl phosphatidylcholine at various temperatures and water concentrations and for the same compound ... -
Brillouin Scattering from Smectic Liquid Crystals
Liao, York; Clark, Noel A.; Pershan, Peter S. (American Physical Society, 1973)Brillouin-scattering results are reported for monodomain samples of \(\beta\)-methyl butyl p [(p-methoxy benzylidine)amino] cinnamate in both the smectic-A and -B phases. For both phases theoretical predictions are confirmed ... -
C60-Propylamine Adduct Monolayers at the Gas/Water Interface: A Brewster Angle Microscopy and X-Ray Scattering Study
Fukumo, Masafumi; Penanen, Konstantin; Heilmann, Ralf K.; Pershan, Peter S.; Vaknin, David (American Institute of Physics, 1997)Brewster angle microscopy (BAM), x-ray specular reflectivity and grazing-incidence x-ray diffraction (GID) studies of C60-propylamine adduct monolayers at the gas/water interface as a function of molecular area are reported. ... -
Capillary Filling of Anodized Alumina Nanopore Arrays
Alvine, Kyle J.; Shpyrko, Oleg G.; Pershan, Peter S.; Shin, Kyusoon; Russell, Thomas P. (American Physical Society, 2006)The filling behavior of a room temperature solvent, perfluoromethylcyclohexane, in approximately 20 nm nanoporous alumina membranes was investigated in situ with small angle x-ray scattering. Adsorption in the pores was ... -
Capillary Wave Fluctuations and Intrinsic Widths of Coupled Fluid-Fluid Interfaces: An X-ray Scattering Study of a Wetting Film on Bulk Liquid
Fukuto, Masafumi; Gang, Oleg; Alvine, Kyle J.; Pershan, Peter S. (American Physical Society, 2006)An x-ray specular reflectivity (XR) and off-specular diffuse scattering (XDS) study of the coupled thermal capillary fluctuations and the intrinsic profiles of two interacting fluid-fluid interfaces is presented. The ... -
Capillary Waves on the Surface of Simple Liquids Measured by X-Ray Reflectivity
Braslau, A.; Pershan, Peter S.; Swislow, G.; Ocko, B. M.; Als-Nielsen, J. (American Physical Society, 1988)The properties of the liquid-vapor interface for three simple liquids (water, carbon tetrachloride, and methanol) have been measured using x-ray reflectivity. The measured surface roughness is interpreted using a model ... -
Capillary-Wave Roughening of Surface-Induced Layering in Liquid Gallium
Regan, M. J.; Pershan, Peter S.; Magnussen, O. M.; Ocko, B. M.; Deutsch, M.; Berman, L. E. (American Physical Society, 1996)The temperature dependence of surface-induced atomic layering in liquid gallium has been investigated with x-ray reflectivity. The prominent layering peak at \(q_z\)=2.4 Å\(^{-1}\) decreases dramatically upon heating from ... -
Competition between Surface Layering and Surface Phase Formation in Dilute Liquid Hg−Au Alloys
DiMasi, E.; Tostmann, H.; Ocko, B. M.; Pershan, Peter S.; Deutsch, M. (American Chemical Society, 1999)We present temperature-dependent X-ray reflectivity measurements of liquid Hg alloyed with 0.06−0.20 atom % Au. At low Au concentrations, we find temperature-dependent surface-induced layering similar to that observed in ... -
Complete Wetting of a Rough Surface: An X-Ray Study
Tidswell, I. M.; Rabedeau, T. A.; Pershan, Peter S.; Kosowsky, S. D. (American Physical Society, 1991)The evolution of the surface structure of a wetting film on a rough surface as a function of the film thickness has been studied by x-ray specular reflection and surface diffusion scattering. For thin films (\(\lesssim\)60 ... -
Confinement-Induced Order of Tethered Alkyl Chains at the Water/Vapor Interface
Fukuto, M.; Heilmann, R. K.; Pershan, Peter S.; Yu, S. M.; Soto, C. M.; Tirrell, D. A. (American Physical Society, 2002)Packing of tethered alkyl chains in Langmuir monolayers of a hairy-rod polypeptide poly[γ-4-(n-hexadecyloxy)benzyl α,L-glutamate] on water has been studied by x-ray scattering measurements at room temperature. The rods lie ... -
Critical Casimir Effect in Three-Dimensional Ising Systems: Measurements on Binary Wetting Films
Fukumo, Masafumi; Yano, Yohko F.; Pershan, Peter S. (American Physical Society, 2005)The critical Casimir force (CF) is observed in thin wetting films of a binary liquid mixture close to the liquid/vapor coexistence. X-ray reflectivity shows thickness (L) enhancement near the bulk consolute point. The ... -
Crystalline monolayer surface of liquid Au–Cu–Si–Ag–Pd: Metallic glass former
Mechler, S.; Yahel, E.; Pershan, Peter Silas; Meron, M.; Lin, B. (AIP Publishing, 2011)It is demonstrated by means of x-ray synchrotron reflectivity and diffraction that the surface of the liquid phase of the bulk metallic glass forming alloy Au_49 Cu_26.9 Si_16.3 Ag_5.5 Pd_2.3 consists of a two-dimensional ...