Kohji Fukushi

The Infrared Band Shapes of Methyl Iodide in Solutions

The infrared band shapes of methyl iodide in solutions were simulated by the superposition of the Lorentzian functions. The a1-type band was well repoduced by a single Lorentzian function. Its half-width was reasonably explained by the reorientational and vibrational relaxations. The e-type band was reproduced by two Lorentzian functions; one represents the central main peak of the band, while the other is much broader and appears like a background. The half-width of the former was nearly proportional to the Q-branch line spacing in the gas spectrum, while that of the latter seems to be related to the A1-E-type Coriolis coupling.

Molecular structure and conformation of 3-methyl-2-butanone: A gas electron diffraction investigation combined with ab initio calculation and vibrational spectroscopy

Abstract The molecular structure and conformation of 3-methyl-2-butanone (isopropyl methyl ketone) have been investigated by gas electron diffraction. Ab initio SCF calculations at the 4–21G level have been carried out and infrared and Raman spectra have been measured in order to obtain supplementary information for the structural determination. The skew conformer is the most stable with a relative abundance of 90(7)% and the eclipsed conformer is the next most stable. The important structural-parameter values of the skew conformer with the limits of error in parentheses are as follows: rg(CO) = 1.217(2) A, rg((O)CC)av = 1.525(1) A, rg((C)CC)av = 1.534(1) A, rg(CH)av=1.113(2) A, ∠αC3C2C4=118.0(8)°, ∠αO1C2C3=120.8(14)°, ∠αC2C3C5=108.0(10)°, ∠αC2C3C6=113.4(12)°, ∠αC5C3C6=111.7(21)°, ∠αHCHav=108.7(8)° and o1(O1C2C3H7)=140(4)°. The dihedral angel, o1, is defined as zero when the O1C2C3H7 fragment is eclipsed.

Vibrational spectra and conformation of diallyl disulphide in the liquid state

Abstract The infrared and Raman spectra of diallyl disulphide have been measured in the liquid state. Normal-coordinate analysis was performed with the structural parameters of the five leading conformers being obtained from molecular-mechanics calculations. It is concluded that diallyl disulphide in the liquid state adopts only the gauche conformation about the CS bonds, while the anti conformation would be made unstable by intermolecular interactions and that a G (+) G (−)- G (+)G(−) sequence is the leading conformation.

Raman spectra of InI, InI2 and InI3. Correlation between structure and thermodynamic properties of fused InxI1–x mixtures

We have measured the Raman spectra of InI, InI2 and InI3 in both the high-temperature solid and the melt. Each of these materials, except for InI3, undergoes a polymorphic transition at high temperatures that can be detected by recording the Raman spectra as a function of temperature, as well as by scanning calorimetric analyses. The Raman results for InI2 demonstrate that the In+ ion is surrounded by units of the complex anion InI–4; since both InI and InIII exist as separate entities in InI2 it can be called an inhomogeneously mixed-valent compound. These results at room temperature are consistent with the previous i.r. study. The Raman spectra of molten InI2 and InI3 are given by parallel and perpendicular components. The decomposition of the parallel spectrum led to the conclusion that the complex ion InI–4 is stable as a host for anions in the molten InI2. Previous work on the thermodynamic properties of fused InxI1–x mixtures showed that the partial molar entropy of In has a drastic excursion near x= 0.333 (or InI2), whereas in the corresponding region there is a prominent change in the liquid structure from a Coulombic interaction between In+ and I– in molten InI to that between In+ and InI–4 as an anion host. The complex anions are stabilized by covalent bonding centred on InIII because of the magnitude of the stretching force constant K of the In—I bond in InI–4.