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The coordination of carbon atoms in diamond-like carbon (DLC) thin films formed by Ar gas cluster ion beam (GCIB) assisted deposition using fullerene as the carbon source was investigated by measuring near-edge X-ray absorption fine structure (NEXAFS) spectra of the carbon K-edge over the excitation energy range 275–320 eV, using synchrotron radiation. With attention to the peak corresponding to the transition of the excitation electron from a carbon 1s orbital to a π* orbital, relative sp2 contents of various DLC films were estimated. The sp2 contents of the DLC films formed by the GCIB-assisted deposition were observed to be lower than those of the DLC films formed by other methods. The hardness value measured with a nano-indentation technique was found to be strongly related to the sp2 content of the DLC film.

Soft x-ray absorption spectra of oriented films of polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) of several tenth micron in thickness were measured by a transmission method. A similar resolution and the same dependence on the beam incident angle as obtained by a total electron yield method were observed in the oxygen K-edge region, but not in the carbon K-edge. IR spectra of the thin oriented sample films utilized in these measurements indicated their aromatic rings to be parallel to the film plane as found in the thick PET and PEN films. This fact conformed to the spectral change near the oxygen K-edge and gave a further support of the peak assignments made previously. The spectral behavior near the carbon K-edge was interpreted by the saturation effect which was due to the presence of greater number of carbon atoms in a repeat unit than oxygen atoms, and partially by strayed light effects.

A compact photoelectron spectrometer has been constructed to analyze energy, momentum and spin of the electronic states in condensed matter. The spectrometer consists of an electron energy analyzer, lens systems and a spin detector. The spin detector is a low-energy diffuse scattering type instrument with a potential of about 100–250 eV. The detector consists of a 90° deflector, a gold target, a four-section anode and lens systems. The detector is about 0.15×0.05×0.05 m3 in size and is rotatable along a single axis in the analysis chamber under ultra-high vacuum conditions. The parameters of the optical elements have been determined through optimization of the photoelectrons from GaAs(100) and with reference to the ray tracing calculation. The performance of the spin detector has been verified by observing the spin-polarized electrons from O/Cs/GaAs(100).

The desorption, dissociation and orientation of oxygen admolecules on a reconstructed Pt(110)(1×2) were studied by means of TDS combined with isotope tracer, NEXAFS, and angle-resolved TDS. The admolecules below half a monolayer lie on the bottom of the trough, being oriented along it. The molecules adsorbed additionally are lying on declining terraces. The desorption flux of the former species shows a simple cosine distribution, suggesting that the molecule is not localized on the bottom in the desorption event.

Luminescence from electron-bombarded YBa2Cu3O7-x was investigated. It has been found that the luminescence is similar in shape and energy position to the vibronic luminescence due to the CN- molecule, indicating that the luminescence is attributed to the CN- adsorbed on the YBa2Cu3O7-x surface but not to the luminescence of intrinsic origin.

The authors would like to thank Mr. M. Fujisawa of Synchrotron Radiation Laboratory of IS SP, University of Tokyo for reflectivity measurements, Prof. T. Saito, Tokyo University of Agriculture and Technology, for ellipsometry measurements, and Stanley Electric Co., Ltd. for EPMA measurements. This work has been partly supported by the financial contribution from Nippon Steel Co., Ltd.

A collective report is given on the recent studies of the energy spectra of thermally stimulated exoelectrons from alkali halides irradiated with X-rays at 77 K. To obtain significant information regarding the exoelectron emission mechanism, the energy spectra and the surface potential were simultaneously measured in a clean high vacuum. On the basis of an identification of the origin of exoelectrons, the observed energy spectra are compared with previously proposed exoelectron emission models. It is stressed that the space charge and the patch field play important roles in the transport and escape processes of exoelectrons after they are released from color centers through thermal or Auger process.

The X-ray K spectra of the transition-metals chromium through nickel and their oxides, chlorides and complexes have been measured with a two-crystal spectrometer. The Kβ5 emission spectra have been obtained with the fluorescent excitation method. The structures which appear in the spectra of the complexes are generally sharp and the molecular orbital theory is appropriate for interpreting these spectra. In the case of the oxides and the chlorides of iron, cobalt and nickel, the observed K spectra show the complicated features. The weak structures which appear in the high energy region of the emission peaks of these substances might be ascribed to satellites.

Thermally stimulated exoelectron emission (TSEE) in KCl: Tl, KCl: Cu and undoped KCl cleaved in a clean high vacuum and X-rayed at liquid nitrogen temperature, is measured simultaneously with thermoluminescence (TL). On the basis of F-light stimulation experiments and close correlations between TSEE and TL, the main TSEE glow peaks are ascribed to the thermal annihilation of color centers. Among these, the TSEE glow peak at about 210 K in KCl: Tl and KCl: Cu is ascribed to the diffusion of VK centers and the subsequent reaction of these centers with electron-excess centers such as F' centers, while the TSEE glow peak at 207 K in undoped KCl is due to the thermal release of electrons from F' centers. The mechanism of the exoelectron emission due to the annihilation of VK centers may be interpreted in terms of a kind of Auger effect.

Crystal-and evaporated film-type KCI were irradiated with X-rays and studied for optically stimulated exoelectron emission (OSEE). Special attention was paid to sample treatment in a clean high vacuum system and to the charging of samples. Upon studying the effects of dose, acceleration voltage and temperature on the OSEE yield spectra, it was shown that when KCI surfaces are clean and non-electrostatically charged, the yield spectra had no “Selective features”. From the OSEE energy spectra that were measured at temperatures sufficiently high to avoid any charging effects, it was found that the threshold energy increased linearly with the photon energy when the latter exceeded 3.4 eV. These results indicate that a direct photoionization from F centers dominates the OSEE mechanisms for KCI and that a two-step process of photo-thermal ionization from the F centers is not important.

Simultaneous measurements of the energy spectra of thermally stimulated exoelectrons and of the surface potential are carried out on KCl:Tl X-irradiated at 77 K. It is found that high energetic exoelectrons are emitted when the sample surface is charged up positive and that the width of their energy spectra is larger than the non-uniform spread of the surface potential (patch field). These results suggest that the energy spectra of the thermally stimulated exoelectrons from KCl:Tl may be interpreted using a space charge model, in which the exoelectrons are accelerated by the internal electric field and are scattered by the optical modes of lattice vibrations during the transport of the exoelectrons to the surface, although the patch field effect also is thought to contribute to the energy spectra of the exoelectrons.