Magnetic circular dichroism of theA andB bands in KI:Ga+, KI:In+, and KI:Sn2+

Magnetic circular dichroism (MCD) of theA- andB-absorption band region has been obtained at 4.2 K and 50 kG in KI:Ga⁺, KI:In⁺, and KI:Sn²⁺. The MCD spectra indicate the complex nature of these bands more clearly than the absorption spectra themselves do. TheA-band MCD consists in all cases of a positive and a negative part reflecting the structure of the absorption band. TheB-band MCD shows three peaks, two positive peaks at 4.34 and 4.41₅ eV (4.09 and 4.17₅ eV) and a negative peak at 4.38 eV (4.12₅ eV) in KI:Ga⁺ (KI:In⁺). TheB-band in KI:Sn²⁺ consists of a shoulder (b ₀) at 3.76 eV and a main band which has at least 5 sub-peaks (b ₁~b ₅) at 3.82₁, 3.84₁, 3.86₁, 3.88₀, and 3.89₅ eV; each of the subpeaks (b ₁~b ₅) gives a derivative-like MCD.The MCD shape functionf() for the transitiona _1g ² a _1g t _1u has been obtained for one set of parameter values by using the classical Franck-Condon approximation and the Monte Carlo integration method. The result can explain the observed salient features of theB- as well asA-band MCD's, indicating the validity of the Franck-Condon approximation and the interaction mode coordinates.     

Dibenzylmagnesium-Initiated Anionic Oligomerizations of trans-Stilbene, 1,1-Diphenylethylene,and α-Methylstyrene in Hexamethylphosphortriamide

trans-Stilbene, 1, 1-diphenylethylene, and α-methylstyrene were allowed to react with dibenzylmagnesium to form their oligomers in hexamethylphosphortriamide (HMPA). One and two molecules of stilbene and 1, 1-diphenylethylene were incorporated into the magnesium carbon bond, and the carbanions obtained in HMPA were stable in analogy with the anionic living polymer having alkali cation as the gegenion in eithers. Intense coloration was observed during the reaction between α-methylstyrene and dibenzylmagnesium as well as in the case of stilbene and 1, 1-diphenylethylene. The low molecular weight products which were formed after a long time in the reaction between α-methylstyrene and dibenzylmagnesium were found to have no magnesium-carbon bond. It was considered that the cleavage of the propagating chain occurred gradually after the rapid propagation had proceeded to consume the monomer.     

Synthesis of ZrO<Subscript>2</Subscript> nanoparticles for liquid scintillators used in the detection of neutrinoless double beta decay

We synthesized liquid scintillators incorporating ZrO₂ nanoparticles for application in neutrinoless double beta decay experiments. ZrO₂ nanoparticles of less than 10 nm in size were synthesized with sub- and supercritical hydrothermal methods. The Zr concentrations in the liquid scintillators were determined to be up to 1.4 wt% with inductively coupled plasma analysis, and the liquid scintillators were transparent to scintillation. These results indicate that these methods are applicable for the preparation of liquid scintillators for neutrinoless double beta decay experiments.     

The Effects of Sulphate and Tartrate Ions on the Molecular Organization of Water: Towards Understanding the Hofmeister Series (VI)

Using the 1-propanol (1P) probing methodology we have developed earlier, we characterized the effects of sulphate and tartrate anions on the molecular organization of H₂O. The results indicate that these two large anions belong to a new class of ??hydrophobe-like hydration center??. That is, sulphate and tartrate ions act as ??hydration centers?? with the hydration number 14±3 for both, and leave the bulk H₂O, away from hydration shells, unperturbed in the absence of the probing 1-propanol. As the mole fraction of the probe increases, however, the hydrogen bond probability of bulk H₂O away from hydration shells appears to decrease smoothly, as occurs with ??hydrophobes?? in H₂O. We plot the negative hydration number against the power to reduce the hydrogen bond probability of bulk H₂O for the two large anions. We also plotted the characteristic indices for ??hydrophiles?? and ??hydration centers?? whose characteristics we determined in the same manner earlier. H₂O defines the origin on this map. We found that a typical Hofmeister ranking for each anion matches reasonably well with that of the distance from the origin for each ion, in decreasing order starting from ions plotted in the north-west quadrant (representing the ??hydrophobe-like?? behavior) of the map and then in increasing order from the origin towards the south on the ordinate, the ??hydrophile-like?? behavior. These findings could be useful in understanding the Hofmeister series, pointing to the importance of the contribution made by the effect of each ion on H₂O, in addition to helping understand direct ion-protein interactions.     

Large electro‐optic activity and enhanced temporal stability of methacrylate‐based crosslinking hyperbranched nonlinear optical polymer

A methacrylate‐based crosslinking hyperbranced polymers have been synthesized through initiator‐fragment incorporation radical polymerization and used for the temperature stable electro‐optic (EO) polymer application. This polymer consists of methyl methacrylate, 2‐metacryloxyethyl isocyanate, and ethylene glycol dimethacrylate (EGDMA) monomers. The use of EGDMA as a bifunctional unit resulted in the solvent‐soluble crosslinking hyperbranched chain, so that the EO polymer enhanced glass transition temperatures. A phenyl vinylene thiophene vinylene bridge nonlinear optical chromophore was attached to the polymer backbone as the side‐chain by a post‐functionalization reaction. The loading concentration of the chromophore was varied between 30 and 50 wt % by simply changing the mixing ratio of the precursor polymer to the chromophore. The synthesized EO polymers produced optical quality films with a light propagation loss of 0.61 dB/cm in a slab waveguide at 1.31 μm. The electrically poled film had an EO coefficient (r₃₃) of 139 pm/V at 1.31 μm. The EO crosslinking hyperbranced polymer had a high‐glass transition temperature of 170 °C, and exhibited excellent temporal stability of the EO activity at 85 °C for 500 h. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012