7,847 research outputs found
The Critical Crossover at the n-Hexane - Water Interface
According to estimates of the parameters of the critical crossover in
monolayers of long-chain alcohol molecules adsorbed at the n-hexane - water
interface, all systems in which this phenomenon is observed are characterized
by the same value of the critical exponent \approx 1.8.Comment: 5 pages, 2 pictures, 1 tabl
Compact Layer of Alkali Ions at the Surface of Colloidal Silica
The forces of electrical imaging strongly polarize the surface of colloidal
silica. I used X-ray scattering to study the adsorbed 2-nm-thick compact layer
of alkali ions at the surface of concentrated solutions of 5-nm, 7-nm, and
22-nm particles, stabilized either by NaOH or a mixture of NaOH and CsOH, with
the total bulk concentration of alkali ions ranging from 0.1- to 0.7-mol/L. The
observed structure of the compact layer is almost independent of the size of
the particles and concentration of alkali base in the sol; it can be described
by a two-layer model, i.e., an ~ 8 Angstrom thick layer of directly adsorbed
hydrated alkali ions with a surface concentration 3x10(18) m(-2), and a ~ 13
Angstrom thick layer with a surface concentration of sodium ions 8x10(18)
m(-2). In cesium-enriched sols, Cs+ ions preferentially adsorb in the first
layer replacing Na+; their density in the second layer does not depend on the
presence of cesium in the sol. The difference in the adsorption of Cs+ and Na+
ions can be explained by the ion-size-dependent term in the electrostatic Gibbs
energy equation derived earlier by others. I also discuss the surface charge
density and the value of surface tension at the sol's surface.Comment: 32 pages 10 figure
Quantum spin metal state on a decorated honeycomb lattice
We present a modification of exactly solvable spin-(1/2) Kitaev model on the
decorated honeycomb lattice, with a ground state of "spin metal" type. The
model is diagonalized in terms of Majorana fermions; the latter form a 2D
gapless state with a Fermi-circle those size depends on the ratio of exchange
couplings. Low-temperature heat capacity C(T) and dynamic spin susceptibility
\chi(\omega,T) are calculated in the case of small Fermi-circle. Whereas
C(T)\sim T at low temperatures as it is expected for a Fermi-liquid, spin
excitations are gapful and \chi(\omega,T) demonstrate unusual behaviour with a
power-law peak near the resonance frequency. The corresponding exponent as well
as the peak shape are calculated.Comment: 4 pages, 3 figure
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