Isotopic effect in the broadening of the energy spectra of fragments of hydrogen molecular ions scattered from surface

The effect of broadening of the energy spectra of fragments of different hydrogen molecular ions scattered from a tungsten surface has been investigated experimentally and by computer simulation. The experimental results are approximated within the explosive model. The contributions of different mechanisms to the broadening of the energy spectra of scattered fragments are discussed.     

Continuum energy spectra of 3He scattered by 3He at 120 MeV

Bump structure was observed in the continuum energy spectra of ³He from the ³He(τ, τ') reaction at 120 MeV. The angular dependence of the cross sections at around the peak of the bump was reproduced by calculations based on the simple impulse approximation. It is also shown that the effects of multiple scattering are important to reproduce the energy spectrum of the lower-energy side of the bump.     

Flavor structure of the electroweak spectra of monoenergetic solar neutrinos scattered by electron

Electroweak and electromagnetic contributions to the spectrum of beryllium solar neutrinos scattered by an electron are investigated. The flavor structure of the electroweak spectrum with the content of electron neutrinos and admixture components ν _μ and ν _τ is analyzed.     

High resolution measurements of energy spectra of protons scattered from silicon crystals in the case of planar channelling

The energy spectrum of backscattered protons in the case of incidence along several planar directions shows a fine structure near the high-energy edge. This structure, an oscillatory dependence of the probability of backscattering vs. depth in the crystal, offers a possibility to study the proton trajectory in the lattice and also to obtain the stopping power of protons near planes in silicon.

Application of a simple model for the proton trajectory yields a stopping power near the planes 4 to 5 times higher than for random incidence. These effects have been observed using primary energies in the range 40–140 keV and for incidence along (110). (111), (100) and (112) planes.     

Interpretation of electronic spectra by configuration analysis: Absorption spectra of monosubstituted naphthalenes

The electronic absorption spectra of four monosubstituted naphthalenes, α-, β-naphthols, and α-, β-naphthylamines have been investigated by means of configuration analysis with particular attention to the dependence of spectra on the position of substitution and on the electron-donating power of the substituent. The results of molecular orbital calculations based on the Pariser-Parr-Pople method are analyzed in terms of locally excited states and intramolecular charge-transfer configurations. The characteristic changes in location and polarization of the L_b, L_a, and B_b bands caused by substitution at the α- or β-position are adequately explained by the analysis. Two strong absorption bands of α-substituted naphthalenes, which appear in place of the B_b band of naphthalene, are shown to result from a mixing of the $\text{B}{}_{\mathrm{3u}}{}^{\mathrm{+}}\text{(B}{}_{\mathrm{b}}\text{)}$ and $\text{A}{}_{\mathrm{g}}{}^{\mathrm{?}}$ states. The amino group exerts a great influence on the electronic structure of the parent molecule, so that the B_b band cannot be identified in the spectrum of β-naphthylamine.     

Interpretation of S-state ion E.P.R. spectra

Although a considerable body of data exists on the parametrization of the ground-state splittings of S-state ions in crystals, relatively little progress has been made in obtaining a quantitative understanding of the mechanisms which determine these parameters. In the course of summarizing our present understanding, we emphasize the need for making planned experiments explicitly aimed at testing theoretical models, such as those proposed in this article. The variable frequency E.P.R. technique is described in some detail, as it has proved to be particularly useful in this respect.     

激光等离子体受激Raman散射光谱的时间分辨测量

采用光学多道谱仪和光学条纹相机耦合,组成时间分辨的Raman散射光谱测量系统,可实现0.5 nm的光谱分辨和好于10 ps的时间分辨。采用该测量系统,在神光Ⅱ装置上开展了脉宽1 ns、波长351 nm的激光与两种不同尺寸柱腔靶相互作用的物理实验,获得了时间分辨的SRS光谱实验结果。研究表明,SRS光谱在时间上相对于入射激光有一定的延迟,腔靶尺寸减小时,延迟时间随之减小。通过长、短波截止波长分析电子密度方法,计算得出了Ⅰ型和Ⅱ型腔靶SRS散射光最短波长光谱发生的密度区分别为0.069nc和0.027nc。     

激光等离子体受激Raman散射光谱的时间分辨测量

采用光学多道谱仪和光学条纹相机耦合,组成时间分辨的Raman散射光谱测量系统,可实现0.5nm的光谱分辨和好于10ps的时间分辨。采用该测量系统,在神光Ⅱ装置上开展了脉宽1ns、波长351nm的激光与两种不同尺寸柱腔靶相互作用的物理实验,获得了时间分辨的SRS光谱实验结果。研究表明,SRS光谱在时间上相对于入射激光有一定的延迟,腔靶尺寸减小时,延迟时间随之减小。通过长、短波截止波长分析电子密度方法,计算得出了Ⅰ型和Ⅱ型腔靶SRS散射光最短波长光谱发生的密度区分别为0.069nc和0.027nc。     

Interpretation of secondary ion mass spectra by means of fingerprint spectra and secondary ion imaging

A passive layer, of several thousand ? thickness, formed on a polycrystalline nickel electrode, has been examined using secondary ion mass spectrometry (SIMS) by spottering with a 5.5 keV, 13μA·cm⁻²,⁴⁰Ar⁺ primary beam. Concentration profiles were detived by monitoring the intensities of atomic and molecular mass peaks as a function of sputtering time (i.e. depth). Nickel was present throughout the layer but not as the element since the relative intensities of the Ni _n ⁺ (n=1, 2, 3, 4) peaks, constituting part of its fingerprint spectrum, differed from those in the fingerprint spectrum of elemental nickel. These values were eventually reached, signifying piercing of the layer and thus providing a means of estimating its thickness. Imaging of⁵⁸Ni⁺ showed the presence of nickel in at least two different modifications in the layer, both with higher Ni⁺ yields than the bulk nickel. Their fractional coverages were estimated from the images taken at various depths. The resulting profile of the Ni⁺ originating from one of these modifications was found to be proportional to the¹⁶O⁻ profile, indicating that these ions originate from the same molecule. This example demonstrates the advantage of combining different SIMS modes (viz. depth profiles, fingerprint spectra and imaging) in tackling certain analytical problems.     

Interpretation of ghost lines in secondary-electron spectra determined by XPS

The photoelectron energy corresponding to the Fermi level of an investigated specimen and the onset energy for detection of secondary electrons are two characteristic energy values that can be used for work-function evaluation. Secondary-electron onset measurements are usually carried out by applying an acceleration voltage between the specimen and the spectrometer entrance, giving a structured secondary-electron spectrum showing three types of secondary electrons: those from the specimen, those from the entrance-slit system, and those from the X-ray tube window. For the latter electrons the electrical field built up in the sample chamber acts as an energy analyzer, imaging a discrete energy interval onto the spectrometer entrance slit. The variation of energy and intensity of these “ghost-lines” is discussed as a function of the applied acceleration voltage and the specimen tilting angle, leading to optimized experimental parameters for recording of secondary-electron spectra.     

Interpretation of the vibrational spectra of polycrystalline adenine

The infrared and Raman spectra of the tetramer of the adenine N₉H are calculated and analyzed. The vibrational spectra of polycrystalline adenine are interpreted. It is demonstrated that the method for calculating the vibrational spectra of molecular complexes formed by hydrogen bonds can be used for interpreting the vibrational spectra of polyatomic molecules in the solid state.     

Interpretation of acceptor spectra in semiconductors

The acceptor Hamiltonian proposed in 1955 by Kohn and Luttinger is extended to introduce the q-dependence of electronic screening and the coupling with the split-off valence band. Accurate solutions of the resulting equations by the irreducible-tensor technique allow a good interpretation of the spectra of the shallow acceptors in Si and Ge.     

Detection of low energy scattered X-rays using charged spheres

To detect low energy scattered X-ray dose below 9.5 keV simply, we have designed a low energy X-ray detector that uses multiple electrically charged conductive spheres floated by static electricity repulsion force. This detector detects the dose with the following steps (principles): (1) positive and negative ions are generated by ionization function of low energy X-rays projected in the detector; (2) those ions neutralize the electrically charged conductive spheres floated; (3) accordingly, the spheres fall; and (4) the detector detects low energy X-ray dose from the number of the conductive spheres fallen. This paper verified performance of this detector.     

Interpretation of the photoelectron spectra of molecularly adsorbed CO

We have measured the photoemission spectra both for CO adsorbed on Ni and Pd films and for gas phase CO over a wide photon energy range. The comparison of these two sets of measurements lead to the following interpreation of the two observed electronic energy levels of molecularly adsorbed CO. The lower binding energy CO-induced level corresponds to the 1π gas phase level with some admixture of the 5σ level and the higher binding energy level corresponds to the 4σ gas phase level. The hω-dependence of the photoionization cross section is shown to play a predominant role in determining the surface sensitivity.