Excimer states of anthracene have been found not only in the crystalline phase at high temperatures but also in the liquid phase by observing stationary and time-resolved fluorescence spectra. Fluorescence decay times in the liquid phase are very short, 0.2-0.3 ns, without any emission wavelength dependence even at the excimer band. On the other hand, there seems to appear a separate component around the excimer band of pyrene liquid, of which the origin is tentatively assigned to a monomer emission band. The change of profiles in Raman spectra of anthracene at the transition from crystal to liquid has been observed and discussed in relation to the disordered and/or ordered structures.

The IR and Raman spectra of bis(methylthio)mercury and methyl(methylthio)mercury were studied. Fundamental vibrations were assigned as follows: frequencies 698, 330, 530 and 174 cm−1 to C–S stretching, S–Hg stretching, C–Hg stretching and C–S–Hg bending vibrations, respectively. The fundamental vibrations were confirmed by normal coordinate analysis. The force constants of S–C and S–Hg stretching vibrations were estimated to be 2.16 and 1.5 md/Å, respectively.

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The electrical resistance of black phosphorus single crystals at low temperatures was analyzed as functions of temperature and magnetic field. Logarithmic dependence of the conductivity on both variables was found. This fact, together with the negative magnetoresistance observed at 4.2 K, suggests the existence of the two dimensional Anderson localization of valence-band holes in black phosphorus single crystals at low temperatures.

The infrared spectra of tris-(acetylacetonato) complexes of praseodymium(III), neodymium-(III), europium(III), gadolinium (III), dysprosium(III), and erbium(III) have been measured in the range between 4000 and 100 cm-1 in order to obtain information about the nature of lanthanide metal-oxygen bond; some properties of these complexes were studied, also. The calculated frequencies and assignments were used to elucidate the complex spectra and to show the relations between the calculated force constants and some physicochemical properties. Although the molecules of each complex were 1 : 3 complexes, the calculation of the vibrational frequencies was made by using a simplified model of the 1 : 1 complex (C2v), because it may be supposed that this tris-(acetylacetonato) complex does not always have a regular octahedral symmetry in spite of the composition of Ln(acac)3. The calculated frequencies were in good agreement with the observed ones; the lanthanide metal-oxygen stretching vibrations were found at 420-432 cm-1 (A1-v5) and 304-322 cm -1 (B1-v14). The lanthanide metal-oxygen stretching force constant increases with an increase in the atomic number, while the corresponding C=O stretching frequency (A1-v1) decreases in the same order. For example, the values of K(Pr-O) and K(Er-O) are 2.10 and 2.29 and/A respectively. As the result of the lanthanide contraction, the force constant of the lanthanide metal-oxygen bond increases with a decrease in the M-O The preparations and infrared spectra of acetylacetonate complexes of various metal ions,1-13) especially of the first transition metal ions, have been studied by many investigators.In this paper, some systematic studies of tris-(acetylacetonato) lanthanide(III) complexes, Ln(acac)3, that is, their preparations, the measurements of the infrared spectra in the 4000-100 cm-1 region, the calculation of the stretching force constants of the metal-oxygen bonds of these complexes, and some physico-chemical properties, will be presented. Furthermore, the relations of the overall stability constants, the electronegativities of lanthanide metal ions, and the M-O bond distances to the band shifts and the force constants of metaloxygen bonds will be discussed.