Hitoshi Kamada

Photoelectron diffraction effects in XPS angular distributions from GaAs(110) and Ge(110) single crystals

Abstract Angular distribution measurements of XPS intensities have been made for various spectral lines from GaAs(110) and Ge(110) single-crystal surfaces. Observed angular distribution curves (ADCs) showed steep intensity variations and sharp peaks due to X-ray photoelectron diffraction (XPED) phenomena. The effects of the type of transition process (photoelectron or Auger), electron kinetic energy and crystal structure on the XPED patterns were examined. Considerably different ADC patterns were observed for high-energy photoelectrons and Auger electrons and for low-energy photoelectrons. ADCs for Ga 3d, As 3d and Ge 3d showed almost the same patterns for scans of the type [110] → [100] → [1 1 0], but they showed substantially different patterns for [110] → [11 1 ] → [00 1 ] scans. These features correspond well with the structural characteristics of GaAs and Ge crystals. A discussion of the applicability of XPS angular distribution measurements to the geometric analysis of crystal surfaces is presented.

Some considerations on the out-of-plane vibration bands of PhnX type molecules in the 800-670 cm−1 region in relation to the estimation of the twist angle θ of benzente rings from their intensities

Abstract The i.r. intensities of the out-of-plane CH bending and the ring out-of-plane deformation vibrations of 11 Ph n X type molecules ( n = 2 or 3) were analyzed in terms of the simple model that, when the intensities of the two modes belonging to the same symmetry species are summed up, the relative magnitudes between those sums belonging to the different species are determined by the twist angle θ of benzene rings. It was shown that the analysis of the intensities always yields the proper values of θ under one of the assumed assignments of the bands; thus, the assignments were examined in relation to the obtained values of θ . Finally, the spectra of the samples in CS 2 rigid solutions at low temperature were presented and discussed from a similar viewpoint.

Determination of gases in metals by an improved vacuum fusion method

Abstract An improved gas extraction, collection, pressure measurement and calculation apparatus is described for use in the vacuum fusion method. It is designed for routine analysis and versatility in research investigations. The time required for gas collection is 1–2 min, including 15–60 sec for gas extraction. The total time required for a complete analysis is 7–9 min. The operating blank is 0.01–0.03 ml 30 min at 1850°. Analysis of 20 or more samples can be made in 8 hr, including loading, outgassing and gas analysis. A description is given of a newly designed gas extraction recording system for studying the optimum conditions for determination of gases in metals of current interest.

Angular Dependence of XPS Intensities from GaAs (110) Surface

Angular distributions of XPS intensities from (110) plane surfaces of gallium arsenide and germanium single crystals were measured. Along the (001) plane, distributions from these three elements showed similar profiles and good correspondence with Kikuchi-band predictions. However, along the (10) plane, distributions from three elements were different from each other. Only from germanium was good correspondence observed. On the other hand, distributions from gallium and arsenic showed mirror symmetric correspondence with the (001) plane, associated with the crystal structure. From the crystal structure analogy, total gallium arsenide intensity and germanium intensity values were compared, but no clear coincidence was obtained.

Structural and chemical state analysis of the heat-treated Au/GaSb(110) interface by means of angle-resolved X-ray photoelectron spectroscopy (ARXPS).

Angle-resolved X-ray photoelectron spectroscopic (ARXPS) studies were carried out to characterize the Au/GaSb (110) interface. Immediately after the evaporation of gold on the GaSb (110) surface to a thickness of about 85A, angular distribution curves (ABCs) of photoelectron intensities showed no fine structures. After heat treatment at 540°C for 30 minutes, ADCs for Ga3d, Sb4d and Au4f showed explicit fine structures. Furthermore, the ADC for Au4f was quite similar to that for Ga3d. This seems to indicate that the Au atoms were incorporated into the gallium antimonide lattice and were preferentially substituted for Ga atoms.

The determination of light elements by proton excitation and x-ray spectrometry

Abstract Proton excitation is suggested for the X-ray spectrochemical analysis of light elements; a 200-kV proton source and a flat crystal X-ray spectrometer are used. Measurements of the X-ray spectra of B-Kα and C-Kα show that proton excitation is promising for analyses in the soft X-ray region. For boron in nickel base alloy and carbon in low alloy steel and white iron, the calibration curves obtained showed excellent linearity. The detection limits were 0.0014% for boron and 0.0090%, for carbon for counting times of 1 min.

Spectrophotometric Study of the Yttrium-TAC-Zephiramine Ternary Complex

Abstract A yttrium-TAC chelate anion reacts with a benzyldimethyltetradecylammonium chloride(Zephiramine) solution to form a ternary complex. The ternary complex has an absorption maximum at 610 nm in an aqueous solution of a pH range from 7.5 to 8.0. The ternary complex and ytrium-TAC chelate anion are stable for at least 5 hours and 20 minutes, respectively. Beers law is obeyed up to the concentration of 1.2 μg ml−1 of yttrium. Molar absorptivity of the ternary complex is 3.7 × 104 l mol−1 cm−1 at 610 nm and sensitivity for yttrium is 2.4 × 10−3 μ cm−1 per 0.001 of absorbance. The composition of the ternary complex is estimated to be Y(tac)4(Zeph). A number of ions which interfere with the determination could be masked by the addition of various masking agents.

Some considerations about the substituent effect on the infrared absorption intensities of symmetric stretching and bending vibrations of methyl group

Abstract Infrared absorption intensities of symmetric stretching and bending modes of methyl group have been measured for 13 compounds. Quite different dependences of intensities on the substituents attached to methyl group have been observed for each of the two modes. The similarity of the intensity behaviours between the substituent and solvent effects has been referred to. The factors determining the intensity changes have been discussed in terms of the electric effects of substituents. Finally, it is demonstrated that the qualitative understanding of the different intensity behaviours observed for each of the modes is possible with the approximate application of the Valence—Optical theory.

Effects of several experimental parameters on the relative sensitivity factors in spark-source mass spectrometric analysis of steel

Abstract The effects of spark gap, sample electrode size, spark technique, spark position, and energy-pass bandwidth of the ion beam, on the relative sensitivity factors in analysis for trace elements in steel by spark-source mass spectrometry have been investigated by means of electrical-detection, peak-switching techniques. The effects of spark gap and spark position are of the greatest importance. The energy distributions of both matrix and impurity ions were measured. For several elements, changes in spark position produced corresponding changes in the distribution of ion energies. These changes of energy distribution were partly responsible for variations in relative sensitivity factors with changing spark position.

The use of ion-induced x-rays for spectrochemical analysis

The application of ion-induced x-rays to spectrochemical analysis was examined by means of a dispersive method with a flat crystal and a 200-kV ion accelerator. For x-rays of longer wavelength than 10 A, x-ray count rates of the order of 104–105 c.p.s. were obtained; the use of heavy ions such as Kr+, Ne+ and O+ was shown to be effective for x-rays shorter than about 30 A, while protons were more efficient for longer wavelengths. X-Ray excitation efficiencies are almost independent of the atomic shell with which the x-rays are associated and are dependent on wavelength only, indicating that almost all elements can yield K, L or M x-rays of considerable intensity. The x-ray excitation method by proton and heavy ion bombardment was applied to the determination of some light elements, F, O, N and Be. Detection limits of 10 p.p.m. could be readily achieved for these elements.