Mössbauer and infrared spectroscopic studies of novel mixed valence states in cobaltous ferrocyanides and ferricyanides

Novel mixed valence states have been obtained by the treatment of cobaltous ferrocyanides (Co⁺²Fe^II) and ferricyanides (Co⁺²Fe^III) in an ozone flow. The CN stretching bands occur at 2085 cm^–1 for Co⁺²Fe^II and at 2160 cm^–1 for Co⁺²Fe^III. After the ozonization process of Co⁺²Fe^II, an intense band approximately at 2125 cm^–1 is detected. This intermediate band must correspond to a mixed valence state of the type: Fe^II–CN–Co²⁺–NC–Fe^III Mössbauer spectra recorded in situ during the ozonization of Co⁺²Fe^II show the presence of two components: a doublet with isomer shift and quadrupole splitting values close to the cobalti ferricyanide and a very broad line for the mixed valence state. From the Mössbauer and infrared spectra of the aged samples of the Co⁺²Fe^II after ozonization, a relaxation process to the initial state of the samples is observed but the mixed valence state is stable.     

The use of novel water-in-oil microemulsions in microemulsion electrokinetic chromatography

We describe the novel use of water-in-oil (W/O) microemulsions to achieve unique separations in microemulsion electrokinetic chromatography (MEEKC). The choice and concentration of the buffer type, surfactant and co-surfactant were all examined and optimized. Separations of a range of neutral and acidic analytes was shown to be markedly different to that obtained by (oil-in-water) O/W MEEKC. Neutral solutes are separated by virtue of their solubility (log P) values in O/W MEEKC with the more water-insoluble solutes migrating last. This separation process does not occur in W/O, as neutral solutes are not separated in order of log P.     

Mode manipulation in system of coupled microcavities with whispering gallery modes

In recent years the studies of electromagnetic modes in solid spherical microcavities have been of great interest both for their potential applications and fundamental optical properties. A system of coherently coupled microcavities may be called a “photonic molecule” and can be employed in the tight-binding device in order to manipulate photons in micrometer length scale. In this work we demonstrate the possibility of mode manipulation in systems of symmetric photonic molecules formed by placing several high-Q micro-spheres in contact. We observe photonic nanojets that reflect the symmetry of the photonic molecule, with 3 jets located at 120 degrees with respect to each other for the triangular photonic molecule. A benzene molecule-like structure consisting of a 7-microspheres cyclic photonic molecule shows a field emission pattern similar to the spatial distribution of the orbitals of the benzene molecule. We also present some results showing the coexistence of whispering gallery modes and photonic nanojets in the same structure.     

Tunable photon lifetime in photonic molecules: a concept for delaying an optical signal

We experimentally and theoretically studied the photon lifetime spectral distribution in two coherently coupled spherical microcavities of 3-16 microm diameter forming a photonic molecule, which shows a multipeak narrowband modal structure resulting from lifting of the mode degeneracy with respect to the azimuthal quantum number. The results demonstrate the feasibility of photonic molecules as a basis for a multichannel, wavelength-tunable optical delay-line device, which can be used for delay times in the range 10 ps to 1 ns.     

Search for color singlet technicolor particles in p&pmacr; collisions at radicals = 1.8 TeV

We search for color singlet technirho and technipion production in p&pmacr; collisions at sqrt[s] = 1.8 TeV recorded with the Collider Detector at Fermilab. These exotic technimesons are present in a model of walking technicolor. The signatures studied are lepton plus two jets plus E(T) and multijet final states. No excess of events is seen in either final state. We set an upper limit on the technirho production cross section and exclude a region in the technipion mass versus technirho mass plane.