Hitoshi Kanno

Raman spectroscopic evidence for a discrete change in coordination number of rare earth aquo-ions in the middle of the series

Abstract Raman spectra of glassy aqueous rare earth chloride solutions are reported. A drastic change of frequency in the totally symmetric stretching vibration (v1) for the Ln(H2O)3+n ions (Ln3+ = rare earth ion) is observed between Sm and Gd and is interpreted as evidence for a change in the inner-sphere hydration number of rare earth ions in the series.

Raman spectra of glassy aqueous LiX and CaX2 solutions (X = Cl, Br and I) in the low frequency region

Raman spectra of glassy aqueous LiX and CaX2 solutions are obtained in the low frequency region (10–900 cm−1). Two low frequency Raman bands are clearly observed. A qualitative discussion is given for the intensity correlation and observed frequency shifts of these bands with halide ions.

Two glass transitions in the tetraethylammonium chloride—water system: Evidence for a metastable liquid—liquid immiscibility at low temperatures

Abstract The glass-forming composition region of the tetraethylammonium chloride—water system has been determined. The exhtence of a low-temperature liquid—liquid immiscibility is established.

Existence of “nearly free” hydrogen bonds in glassy aqueous calcium perchlorate solutions

Abstract The OH stretching Raman spectra of aqueous calcium perchlorate solutions are obtained in both liquid state at room temperature and glassy state at liquid nitrogen temperature. Nearly free hydrogen bonds caused by perchlorate ions are preserved even in the glassy state.

Cationic and anionic effects on the homogeneous nucleation of ice in aqueous alkali halide solutions

Abstract Homogeneous ice nucleation temperatures ( T H s) of aqueous alkali halide solutions were measured as a function of salt concentration. Cationic effect on T H increases with decreasing ionic radius: Cs + + + + + while anionic effect becomes larger with increasing ionic radius: Cl − − − . There is almost a linear relation between T H and 1/ r + (or 1/ r − ) for the same halide (or alkali) solutions up to high salt concentrations ( r + and r − are ionic radii of alkali and halide ions, respectively).

Drastic changes in the raman spectrum of aqueous gallium chloride solution from liquid state to glassy state

Abstract Raman spectra of aqueous gallium chloride solutions are obtained in both liquid state at room temperature and glassy state. Large spectral changes are observed on going from liquid to glassy state and are discussed in terms of ionic equilibrium reactions.

Liquid Chromatographie separation of polycyclic aromatic hydrocarbons with cerium(IV) oxide as packing material

Cerium oxide (CeO2) was evaluated as a column packing material for liquid chromatography. A pretreated CeO2 slurry was made in ethylene glycol and was forced into a stainless steel tube (125 × 4.6 mm) for 60 min at a constant pressure of ca. 550 kg/cm2. Naphthalene, anthracene, pyrene and chrysene were successfully separated using pure n-hexane as a mobile phase. The column efficiency is approximately 500 theoretical plates. The separation efficiency of the CeO2 column was compared with a commercial silica gel column. The main advantage of the CeO2 column was its improved separation efficiency for phenanthrene and pyrene.

The strong hydrogen bonds in high-density amorphous ice at high pressures

We have investigated the change of in situ Raman spectra of high-density amorphous ice (HDA) as functions of pressure and temperature. Here we show the spectral evidence for the formation of strong hydrogen bonds in HDA at high pressures and the close similarity in spectral features of relaxed HDA to that of supercooled water at high pressures and low temperatures. It can be also suggested that pressure-induced amorphization is a collapsed transition and HDA is not a glassy state of liquid water.

TiO2 based photocatalysts prepared from titanium isopropoxide and aqueous electrolyte solutions

Abstract A simple preparation method for M/TiO 2 photocatalysts (M is metal or metal oxide) is presented together with some preliminary results. It appears that not only surface but also internal electronic structure of the catalyst can be modified by this preparation method.

Existence of H3O+ ions in glassy aqueous HX solutions (X = Cl and Br)

It is shown that oxonium ions are preserved in glassy aqueous HCl and H Br solutions at liquid nitrogen temperature. The ν 1 and ν 2 Raman bands of the H 3 O + ion are more clearly observed in the glassy solution than in the liquid solution at room temperature.