High resolution infrared spectrum and global analysis of ν5, ν12, and ν12 + ν6 − ν6 in CH3SiH3

The vibration-torsion-rotation spectrum of CH₃SiH₃ has been measured from 470 to 725 cm⁻¹ at near-Doppler resolution. The full-width at half - maximum of the lines observed near 600 cm⁻¹ was 0.0011 cm⁻¹. The spectra were obtained using a Bruker IFS 125 HR Fourier transform spectrometer with the broadband source radiation being supplied from the synchrotron emission of the storage ring at the Canadian Light Source. Three vibrational bands were investigated: the lowest lying perpendicular fundamental ν₁₂ centred near 524 cm⁻¹, the lowest lying parallel fundamental ν₅ near 703 cm⁻¹, and the torsional hot band ν₁₂ + ν₆ − ν₆ near 534 cm⁻¹. For ν₁₂ and ν₅, the resolution and sensitivity are much improved over those in earlier studies, with many of the torsional multiplets now being resolved even in the cases where the upper levels are unperturbed. The primary motivation for the present work was the hot band, here reported for the first time, where the dependence of the silyl rock in ν₁₂ on the torsional motion is much more pronounced. In addition, for the vibrational ground state (gs), two “forbidden” high torsional overtones v₆ = 3 ← 0 and 5 ← 0 have been observed that become allowed through resonant mixing of the upper states with ν₁₂ and ν₅, respectively. In each case, two (K, σ) series have been measured where the mixing is largest. Here σ = 0, 1, −1 labels the torsional sub-levels. Using the Fourier transform waveguide spectrometer at E. T. H., the three σ-components of the (J = 1 ← 0) transition in ν₁₂ + ν₆ were observed, and a series of direct l-doubling transitions in ν₁₂ + ν₆ were measured for σ = 0. In a global fit, all the new data have been analysed along with the frequencies for other transitions obtained in earlier investigations. The analysis takes into account the relevant interactions among the torsional stacks of levels in the gs, ν₁₂, and ν₅. These include the previously known (gs, ν₁₂) Coriolis-like and (gs, ν₅) Fermi-like interactions along with a higher order (ν₁₂, ν₅) Coriolis-like coupling introduced here. This last is responsible for the strong perturbation of the ν₅ series with K = 10, 11, and 12, and of the corresponding hot band series. A good fit to 9282 frequencies including 7942 new measurements was obtained both with the Free Rotor model in which the torsion is classified as a rotation, and with the High Barrier model in which the torsion is classified as a vibration. The Hamiltonian is discussed with emphasis on the new terms required for treating ν₁₂ + ν₆ − ν₆.     

二甲基二烯丙基氯化铵/丙烯酸共聚凝胶的辐射合成与性质研究

采用γ辐射溶液聚合法合成了几种二甲基二烯丙基氯化铵 丙烯酸 (DADMAC AA)共聚凝胶 .实验结果表明单位体积溶液中二组分单体总摩尔数和丙烯酸 (AA)相对含量的增加使共聚凝胶力学强度明显增高 .在两种单体等摩尔比的情况下共聚体的凝胶含量随剂量增加而增加 ,且明显高于聚N ,N′ 二甲基二烯丙基氯化铵 (PolyDADMAC)凝胶 .体系中少量κ 卡拉胶 (KC)的加入可增强共聚凝胶韧性但对凝胶含量和强度影响甚微 .共聚凝胶溶胀性能测定结果表明DADMAC与AA摩尔比为 1∶2时凝胶溶胀比与体系pH值的关系呈现聚两性电解质性质 ,等电点pH值接近 4 5 .这种聚两性电解质性质在对铼Re(Ⅶ )离子浓集中也有所表现     

AFM of Metallic Nano-Particles and Nano-Structures in Heavily Irradiated NaCl

AFM investigations are reported for heavily, electron irradiated NaCl crystals in ultra high vacuum (UHV) in the non-contact mode with an UHV AFM/STM Omicron system. To avoid chemical reactions between the radiolytic Na and oxygen and water, the irradiated samples were cleaved and prepared for the experiments in UHV. At the surface of freshly cleaved samples, we have observed sodium nano-precipitates with shapes, which depend on the irradiation dose and the volume fraction of the radiolytic Na. It appears that the nano-struchires consist of (i) isolated nano-particles, (ii) more or less random aggregates of these particles, (iii) fractally shaped networks and (iv) “fabrics” consisting of bundles of Quasi-1D arrays forming polymeric networks of nano-particles. Almost independent of the concentration of the metallic Na in the samples the size of the individual nano-particles is in the range 1–3nm. Our new AFM results are fully in line with our CESR and previous Raman scattering results.     

Radiation-induced degradation of solid fluorene

Degradation of γ-irradiated solid fluorene with different γ-ray doses was investigated in the present work. Dissolution of the γ-irradiated fluorene in aqueous-methanol solution led to the formation of new products as a result of chemical interaction between the trapped electrons and fragments in the host lattice of fluorene with solvent molecules and ions. The new products were identified and separated by UV-Vis., GC/MS and NMR spectroscopy and separated by High Performance Liquid (HPL) chromatography. The new products were identified to be 1,vinyl-cyclopentene, 1,8-napthalenedicarboxylic acid and furan. For explanation of the results, probable reaction mechanisms are given.     

Hydrogen behaviour in electron-irradiated titanium alloys studied by positron annihilation method

Measurements of angular distribution of annihilation photons are applied to investigations of hydrogen behavior in annealed, plastically deformed, and irradiated titanium alloys. It is shown that hydrogen interaction with materials becomes more intensive in presence of structural imperfections of deformational and radiation origin. Probable mechanisms of hydrogen interaction with deformational and radiation defects are discussed.     

Electron-emission activity of defects in surface layers of crystalline and vitreous silica

This paper deals with the photoemission activity of radiation defects in crystalline and vitreous silica. Spectral and kinetic parameters and the concentration of defects in the surface layer and the bulk of the material were determined. Some features of the distribution of radiation-induced defects along the depth of samples having different degrees of order were analyzed. Regularities of relaxation of excited states of emission centers suggested that thermally activated processes were involved in the release of electrons.     

Raman scattering study of ion bombardment induced amorphization of SiC

Abstract

Lattice disorder induced by ion bombardment of SiC surfaces has been studied using Raman spectroscopy. After bombardment with 15 keV H⁺, D⁺ or He⁺ to fluences of 10¹⁹ cm^?2 the SiC surface was found to amorphize as indicated by changes in the Raman spectra. Raman studies of the annealing behavior of the damaged surface showed that no recrystallization of the amorphous layer occurred after 12 hours at 1000°C. By using different wavelengths of the exciting radiation the spatial distribution of the ion induced damage was investigated. Evidence for the preferential sputtering of Si resulting in a carbon rich surface layer is discussed.

Based on work performed under the auspices of the US Energy Research and Development Administration.

By acceptance of this article, the publisher and/or recipient acknowledges the US Government's right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper.     

Josephson junction fabrication by means of ion implantation and electron beam lithography

Josephson junction fabrication techniques by means of ion implantation, electron beam lithography and dry etching process are discussed. Current voltage characteristics, temperature and an applied magnetic field dependence of a maximum zero-voltage current have been measured. Dose dependence of major junction parameters has also been investigated.     

Die amorphisierung von kristallen durch ionenbeschuss und mechanismen von sekundärprozessen

Results of an experimental study of the ion-electron-emission coefficient of monocrystalline and amorphous germanium as a function of the angle of incidence for 10–30 keV Ne⁺, Ar⁺, Kr⁺ ions are presented. Using the concept of ion channeling in crystals the energy dependence of anisotropy of the ion-electron-emission coefficient is explained.     

Implantation angle influence on penetration of boron channelled ions into silicon

Experiments on the dependence of penetration of boron ions channelled into silicon are described.