Synthesis of solid solutions of Cd1-xZnxS nanocrystals in the channels of mesostructured silica films

In this contribution, we introduce the use of metal ion (Cd(ii) and Zn(ii)) modified mesostructured silica as a reaction medium, to produce a solid solution of Cd1-xZnxS nanocrystals as a thin film. With this approach, a true liquid crystalline templating (TLCT) and liquid crystalline mesophase of transition metal salt oligo(ethylene oxide) non-ionic surfactant (((1 - x)[Cd(H2O)4](NO3)2 + x[Zn(H2O)6](NO3)2) CH 3(CH2)11(OCH2CH2) 10OH, (MLC)), systems were collectively used to synthesise mesostructured silica films. The film samples were reacted at room temperature (RT) in an H2S atmosphere to produce zinc blend Cd 1-xZnxS nanocrystals in the channels of mesostructured silica. The initial Zn(ii) and Cd(ii) ion concentrations in the reaction media determine the final composition and band gap of the Cd1-xZn xS nanocrystals. The growth process of the Cd1-xZn xS nanocrystals in the pores is influenced by the silica walls. If the walls are rigid (well polymerized, obtained by aging the samples before H2S treatment), then the Cd1-xZnxS nanoparticles are smaller in size and more uniform in size distribution. © The Royal Society of Chemistry 2006

The Charge Form Factor of the Neutron at Low Momentum Transfer from the 2H⃗(e⃗,e′n)p^{2}\vec{\rm H}(\vec{\rm e},{\rm e}'{\rm n}){\rm p} Reaction

We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The neutron form factor ratio $G^{n}_{E}/G^{n}_{M}$ was extracted from the beam-target vector asymmetry $A_{ed}^{V}$ at four-momentum transfers $Q^{2}=0.14$, 0.20, 0.29 and 0.42 (GeV/c)$^{2}$.Comment: 5 pages, 3 figures, submitted to Phys. Rev. Let

Measurement of the proton electric to magnetic form factor ratio from \vec ^1H(\vec e, e'p)

We report the first precision measurement of the proton electric to magnetic form factor ratio from spin-dependent elastic scattering of longitudinally polarized electrons from a polarized hydrogen internal gas target. The measurement was performed at the MIT-Bates South Hall Ring over a range of four-momentum transfer squared $Q^2$ from 0.15 to 0.65 (GeV/c)$^2$. Significantly improved results on the proton electric and magnetic form factors are obtained in combination with previous cross-section data on elastic electron-proton scattering in the same $Q^2$ region.Comment: 4 pages, 2 figures, submitted to PR

A New Upper Limit for the Tau-Neutrino Magnetic Moment

Using a prompt neutrino beam in which a nu_tau component was identified for the first time, the nu_tau magnetic moment was measured based on a search for an anomalous increase in the number of neutrino-electron interactions. One such event was observed when 2.3 were expected from background processes, giving an upper 90% confidence limit of 3.9x10^-7 Bohr magnetons.Comment: 9 pages; 1 figur