Infrared intensities of ion-water interactions in aqueous electrolyte solutions

The i.r. absorption intensities have been measured of the fundamental vibrations of water molecules in metal halide aqueous solutions. Pseudo-isosbestic points were observed in the regions of both the stretching and bending vibrations and interpreted in terms of two states of water molecules in the solutions. The intensities of the stretching vibrations of water molecules coordinated to the dissolved ions have been estimated. The intensities become stronger in the order, Li⁺ > Na⁺ > K⁺ for the cations and F^- > Cl^- > Br^- > I^- for the anions. These orders are consistent with the strengths of the ion-water interactions, which are related to the dynamical behavior of the water molecules in the primary hydration shell.     

Band shapes and moment analysis of the far-infrared absorptions of dipolar molecules in solutions

The moment analyses were performed on the far-infrared absorption bands of CH₃CN, CHCl₃, CH₂Cl₂, and their deuterated compounds dissolved in nonpolar solvents. The values of torque acting on the solute molecules were estimated from the fourth moments. The band profiles were simulated by means of the continued-fraction representation of the time correlation function by Mori, using the moment values obtained. The third order long-time approximation of the correlation function yields essentially good simulations. The effective rotation angles of molecules between collisions were estimated from the first positive-to-negative turning points of the memory functions. The solvent effects on the torque and the rotation angle were consistent with each other.     

Mössbauer study of amorphous Fe2RE (RE=Ce,Er) alloys

Among amorphous Fe₂RE (RE=Er, Ce, Gd, La, Pr, Sm, Dy, Ho) alloys, Fe₂Ce exhibits a tendency toward short range order, while the other Fe₂RE compounds show clustering. However, we have almost no information about environments around Fe atoms. Using Mössbauer spectroscopy we have determined the quadrupole splitting distributionsP(QS) of two representative amorphous Fe₂RE (RE=Ce, Er) alloys, leading to local environments of Fe atoms. The analysis of the mixed magnetic dipole and quadrupole interactions in Fe₂Er shows two kinds of electrical field gradients (EFT) with the positive and negative signs in the sample, indicating a random packing of Fe atoms. Furthermore, the analyzed quadrupole splitting distributionP(QS) of Fe₂Er also supports random packing in this amorphous alloy. On the other hand, the amorphous Fe₂Ce alloy shows two kinds of distributions of quadrupole splitting; the major component indicating random packing and the minor component Ce-rich Ce-Fe clusters.     

Self-trapping of a wannier exciton in the optical phonon field

Stability for self-trapping of a Wannier exciton in the polarization field of optical phonons is studied by means of variational calculations based on the adiabatic approximation. The phase diagram of free and self-trapped states is presented for 1s, 2s and 2p excitons. It is shown that optical phonons can be responsible for self-trapping of 2s (2p) exciton as a trigger of self-trapping.     

ATR mode of surface magnon polaritons on YIG

The first discussion on ATR mode of surface magnon polaritons on semi- infinite YIG is presented for the Otto configuration (polyethylene-air-YIG geometry). Damping and the effect of retardation are included in the analysis. The thickness of the air layer appropriate for ATR measurements is determined.     

Ionic polarization effects on a shallow exciton at a finite temperature

The effective Hamiltonian for the interaction of a shallow exciton with longitudinal optical (LO) phonons at a finite temperature is derived to first order in the electron-phonon coupling α and E_B/?ω.     

Optical absorption of Cu-centers in CdCl2 and CdBr2 single crystals

The absorption spectra of CdCl₂ and CdBr₂ single crystals doped with cuprous or cupric halides were measured. Optical bleaching of the absorption bands due to Cu⁺ gives rise to new absorption bands which suggest the conversion of Cu⁺→Cu²⁺. This was confirmed also by detecting the growth in ESR signals characteristic of Cu²⁺ centers.