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The solution-phase ionization potentials of I−, Br−, and SCN− ions in 16 solvents including water have been measured by a photoelectron emission spectroscopic technique. The values obtained as the threshold energy Et for halides are found to be correlated well with the Mayer–Gutmann acceptor number and better with the Riddle–Fowkes modified acceptor number of the solvent indicating that the electronic states of the halides are predominantly stabilized through the Lewis acid–base interaction. The reorganization energies ΔGr of solvent after the photoionization of the halides are obtained from the Et values. The experimental ΔGr values are reproduced by using a simple model which incorporates the dipole–dipole repulsion and the bond formation energies in the first solvation layer. The solvation mechanism of SCN− is somewhat different from those of the halides because its Et depends less on the acceptor number and its ΔGr values in alcohols are about half of those for the halides.

The reflectivity was measured at the interface between the glass substrate and the Brilliant Blue (BB) or Methylene Blue (MB) aqueous solution as a function of the angle of incidence at 632.8 nm from a He–Ne laser. The relationship between the reflectivity and the angle of incidence was analyzed by an approximate expression derived from the basic theory of internal reflection spectroscopy. On the other hand, a plot of the reflectivity against the effective thickness was used as a ready diagnosis of the dye adsorbed by the glass substrate. From the results it has been suggested that BB is not adsorbed, whereas MB is. Based on a parameter obtained experimentally, the thickness of the adsorption layer was determined to be 0.65 ± 0.18 nm. This result suggests that the MB cation is adsorbed parallel to the glass surface to form a monomolecular layer. Further, it has been revealed from a similar analysis that the addition of a cationic surfactant with a long alkyl chain in the MB solution prevents the adsorptio...

Strong multielectron excitation structures (MEES) in the extended X-ray absorption fine structure (EXAFS) region have been observed in Br K-edge absorption spectra of tetra-n-propylammonium bromide and bromide ion in aqueous and acetonitrile solutions. The MEES were extracted from the background of EXAFS spectra. The positions of steps due to MEES are well predicted by the Z+1 approximation.

Photopyroelectric (PPE) signal induced by X-ray absorption in a copper foil could be observed by using a thin ferroelectric polyvinylidene difluoride film with aluminium electrodes. An EXAFS was found in each PPE signal intensity and phase spectrum.

X-Ray absorption spectra of hexaaqua and hexaammine complexes of some 3d transition metals in solids and in aqueous solutions are measured and analyzed. It is found that the peak intensities in the EXAFS Fourier transforms for aqua complexes correlate with those for ammine complexes.

Two photosensitive uranyl complexes have been prepared and examined by a single-crystal X-ray diffraction study. Both compounds crystallize in the monoclinic system. In bis(β-ethoxypropionato)dioxouranium(VI), uranyl ions are equatorially coordinated by six carboxylate oxygen atoms, forming one-dimensional infinite chains. In bis(ethoxyacetato)dioxouranium(VI), uranyl ions are equatorially coordinated by four carboxylate and one ethoxy oxygen atoms, forming two-dimensional network of uranyl-ligand infinite chains.

The photoelectron-emission threshold energies were determined for aqueous and alcoholic solutions of potassium hydroxide and potassium metal. The energies correspond to the vertical ionization potentials of the solutes. The results are in accord with the fact that in alcohol-rich solutions the hydroxide ion reacts with alcohol to produce the alkoxide ion. The threshold energy for the alkoxide ion reflects the ionization potential of the alkoxide ion in a vacuum and the solvation effect. The difference in the ionization potential in a vacuum and in a solution, which is due to the solvation effect, was found to correlate with the acceptor number of the solvent.

Temperature change of a sample solution due to optical absorption was detected by a pyroelectric sensor. A calibration curve was linear at the low concentrations of dye and the detection limit was 0.0035 cm−1. From a solvent dependence of the signal magnitude, the signal generation could be explained by thermal conduction.

He I photoelectron spectra of ethylene carbonate, propylene carbonate, γ-butyrolactone, β-propiolactone and vinylene carbonate have been investigated. Assignments of an oxygen lone pair and nonbonding π orbitals have been made by means of analysis of vibrational structures and molecular orbital calculation. Many vibrational structures could be assigned to appropriate vibrational modes of the corresponding neutral molecules from a comparison with infrared and Raman spectra. Correlation among the orbital energies of the compounds is discussed.

Photoacoustic spectrometry was applied to the determination of michroamount of Hg diphenylcarbazone complex. The photoacoustic spectrum and diffuse reflectance spectrum almost agree with each other, showing an absorption maximum at 560 nm, as in the absorption spectrum of the complex in benzene solution. Determination of Hg was performed by measuring the intensity of photoacoustic signal at 560 nm. The normalized signal intensity increased linearly with the amount of mercury ion up to 100 ng, deviating from linear relationship downwards above 100 ng. The photoacoustic signal saturation caused by strong absorption of radiation was investigated.

The first and the second bands of the photoelectron spectra of acetic, propionic, and isobutyric acids were recorded, and the vibrational structures in the spectra were studied by comparing with the results of formic acid. The first band exhibits a νc=o, a δOH, and a ρCOOH vibrational progression, and this implies that an oxygen lone pair orbital, from which the first band of the spectra originates, contributes not only to a C=O bonding and the bonding between carbonyl oxygen and hydroxyl hydrogen, but to the settling of carboxyl group in the molecular plane. The second band exhibits a νc=o, a νc-o vibrational progression with very high frequency for the νc=o as observed in the case of formic acid. Thus the vibrational features of the second band are consistent with the ionization of an antisymmetric π orbital localized mainly on carbonyl and hydroxyl oxygen atoms. Since the 0-0 vibrational transitions for the second ionization are out of the Franck-Condon region, the second adiabatic ionization potential...

Photoacoustic signal induced in a thin region on the solution side at a glass-dye solution interface was measured by changing an angle of incidence. It was contemplated that the method could be extended to observation within the effective thickness as small as 100 nm and on the solution of as low concentration as 10−5 in absorbance.

Binding energies of core electrons in Cr(C6H6)2, Cr(C6H6)(CO)3, and Cr(CO)6 were measured by means of X-ray photoelectron spectroscopic method in solid phase. By comparison with their UPS spectra observed in gasous phase, binding energies referred to vacuum level can be obtained. On the basis of this result, charge distribution in these complexes are estimated. The intramolecular relaxation energy of Cr(C6H6)2 is also discussed.

The electroreduction of [Co(CO3)(NH3)5]+, [Co(CO3)(NH3)4]+, [Co(CO3)(tn)2]+, [Co(CO3)(pn)2]+, [Co(CO3)(en)2]+, and [Co(CO3)2(en)]− (tn=trimethylenediamine, pn=propylenediamine, en=ethylenediamine) have been studied at mercury electrodes in weak acid solutions. All complexes exhibit two irreversible reduction waves; the first corresponds to CoIII→CoII, and the second, to CoII→Co0. The kinetic parameters of the electrode reactions of the first step were determined by means of Tast and pulse polarography in solutions containing 0.005 M sodium acetate-acetic acid buffer (pH=6) and 0.995 M sodium nitrate at 25 °C. The differential pulse polarograp hic characteristics of these complexes are also given.

Photoelectron spectra of cyclohexane, cyclopentane, n-hexane and n-pentane have been studied. The vibrational structures of cyclohexane parent ion were clearly observed. The vibrational spacing is about 1160 cm−1 which can be assumed due to the C–C stretching vibrations. This spectrum was compared with the breakdown curves by charge exchange.

Photonometric titration of thallic ion is described, in which uranous ion, the titrant, is generated by photoreduction of uranyl ion in a sulfuric acid solution containing sodium lactate. Uranyl ion could be reduced with the light at wavelengths longer than 300 mμ, whereas thallic ion could not be reduced with the light in this wavelength range. Selective photoreduction of uranyl ion was accomplished by eliminating wavelengths below 300 mμ with a filter. In this photonometric titration, reaction solutions were irradiated without stirring at 29.5±0.5°C. The absorbance of uranous ion produced was measured at 655 mμ, every fixed irradiation time, and the absorbance was plotted against the irradiation time. Induction period, which means the period during which the absorbance remains actually zero, was in a linear relation with thallic concentration. Thus the titration of thallic ion was satisfactorily carried out in the concentration range from 0.01 to 0.1 mM. The results proved the feasibility of titration i...

Photoelectron spectra of some simple carboxylic acids and halogen substituted acetic acids were observed. Each spectrum contains a band which is associated with the ionization from an oxygen lone pair (n0) orbital of carboxyl group. The band associated with the n0 orbital is clearly separated from other bands, and its shape and width are quite similar among the various carboxylic acids. In the spectra of halogen substituted acetic acids, n0 band appears around the region of the lone pair bands of halogen atoms. The ionization potentials for oxygen lone pair orbital of carboxylic acids are measured and compared with the results of some semi-empirical SCF MO calculations. The agreements are quite satisfactory when ionization potentials are obtained from the difference of total energies of neutral molecule and its corresponding cation calculated using CNDO/2 or INDO method. MINDO/2 method also gives excellent values when Koopmans’ theorem is applied.